A or the

{"tinkumo_explanation_next":true,"questions":[{"content":"<p>I saw a dog in the park. <span class=\"placeholder\">_____</span> dog was black.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["A","The"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I saw a dog in the park. The dog was black.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>My aunt is <span class=\"placeholder\">_____</span> doctor. She works at a hospital.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>My aunt is a doctor. She works at a hospital.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Look at <span class=\"placeholder\">_____</span> moon! It is very bright tonight.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Look at the moon! It is very bright tonight.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I have <span class=\"placeholder\">_____</span> brother and two sisters.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I have a brother and two sisters.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>My friend has a cat and a parrot. <span class=\"placeholder\">_____</span> parrot often sits on his shoulder.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["A","The"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>My friend has a cat and a parrot. The parrot often sits on his shoulder.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>What <span class=\"placeholder\">_____</span> beautiful picture!</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>What a beautiful picture!</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>In summer <span class=\"placeholder\">_____</span> sun sets late in the evening.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>In summer the sun sets late in the evening.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>We go swimming once <span class=\"placeholder\">_____</span> week.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>We go swimming once a week.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Dad bought a cake for my birthday. <span class=\"placeholder\">_____</span> cake was delicious.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["A","The"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Dad bought a cake for my birthday. The cake was delicious.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I brush my teeth twice <span class=\"placeholder\">_____</span> day.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I brush my teeth twice a day.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>There are no clouds in <span class=\"placeholder\">_____</span> sky today.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>There are no clouds in the sky today.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I need <span class=\"placeholder\">_____</span> pen. Can you give me one?</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I need a pen. Can you give me one?</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>There is a box on the table. Please open <span class=\"placeholder\">_____</span> box.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>There is a box on the table. Please open the box.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Is there <span class=\"placeholder\">_____</span> shop near here?</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Is there a shop near here?</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I would like to travel around <span class=\"placeholder\">_____</span> world.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I would like to travel around the world.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I have <span class=\"placeholder\">_____</span> headache today.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I have a headache today.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I got a letter yesterday. <span class=\"placeholder\">_____</span> letter was from my grandmother.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["A","The"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I got a letter yesterday. The letter was from my grandmother.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Let's go for <span class=\"placeholder\">_____</span> walk in the park.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Let's go for a walk in the park.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>My sister plays <span class=\"placeholder\">_____</span> piano every evening.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>My sister plays the piano every evening.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Have <span class=\"placeholder\">_____</span> nice day!</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Have a nice day!</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>This is <span class=\"placeholder\">_____</span> tallest building in our city.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>This is the tallest building in our city.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Can I have <span class=\"placeholder\">_____</span> look at your drawing?</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Can I have a look at your drawing?</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>She is <span class=\"placeholder\">_____</span> best student in our class.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>She is the best student in our class.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>We had <span class=\"placeholder\">_____</span> great time at the party.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>We had a great time at the party.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>January is <span class=\"placeholder\">_____</span> first month of the year.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>January is the first month of the year.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>It was such <span class=\"placeholder\">_____</span> long journey that we were very tired.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>It was such a long journey that we were very tired.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Moscow is <span class=\"placeholder\">_____</span> capital of Russia.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Moscow is the capital of Russia.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>When I grow up, I want to be <span class=\"placeholder\">_____</span> pilot.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>When I grow up, I want to be a pilot.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Where is Mum? She is in <span class=\"placeholder\">_____</span> kitchen.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Where is Mum? She is in the kitchen.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>I want to buy <span class=\"placeholder\">_____</span> present for my mum. What should I buy?</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>I want to buy a present for my mum. What should I buy?</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>My friend and I are in <span class=\"placeholder\">_____</span> same class.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>My friend and I are in the same class.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>My brother has <span class=\"placeholder\">_____</span> cold, so he is staying in bed.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>My brother has a cold, so he is staying in bed.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>There is a big table in <span class=\"placeholder\">_____</span> middle of the room.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>There is a big table in the middle of the room.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>A rose is <span class=\"placeholder\">_____</span> flower.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["the","a"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>A rose is a flower.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Somebody is knocking at <span class=\"placeholder\">_____</span> door. Can you open it?</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":1,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Somebody is knocking at the door. Can you open it?</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]},{"content":"<p>Once upon a time there lived <span class=\"placeholder\">_____</span> king in an old castle.</p>[[gap-1]]","widgets":{"gap-1":{"type":"fill_choice_big","options":["a","the"],"answer":0,"displayMode":"buttons","placeholder":false}},"explanation":"<p>Once upon a time there lived a king in an old castle.</p><p>Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar.</p>","hints":["Use a or an to introduce one unspecified countable thing. Use the when the listener can identify it from an earlier mention, the situation or a unique reference. Common musical-instrument expressions also use the: play the piano or play the guitar."]}]}