Perhaps the day will come ____ people will be able to breathe clean air in cities．

Perhaps the day will come ____ people will be able to breathe clean air in cities．

Perhaps the day will come ____ people will be able to breathe clean air in cities．

1. A.
   when
2. B.
   while
3. C.
   as
4. D.
   since

完形填空

Clean air 1 important 2 health. If there are impurities (杂质) in the 3 , 4 may 5 by our bodies and make us 6 . We need clean air, but 7 , air pollution 8 generally 9 , especially 10 cities.

Now, 11 people are 12 the importance 13 clean air. Schools are now teaching about the pollution problem. Industries are 14 to help clean up their smoke. Scientists are 15 to develop 16 engines for cars. Some day we 17 drive cars that are run by electricity. 18 the day will come 19 people will be able to 20 clean air in cities.

选择最佳答案

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A．more and more

B．the more and the more

C．fever and fever

D．less and less

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完形填空

　　Clean air  1 important  2 health. If  3 contains(含有) impurities (杂质) ,  4 may  5 by our bodies and make us  6 .

　　We need clean air, but  7 air pollution(污染)  8 generally  9 , especially  10 cities. Now  11 people are  12 the importance  13 clean air. Schools are now teaching about the pollution problem. Industries(工业) are  14 to clean up their smoke. Scientists are  15 to develop  16 engines for cars. Someday we  17 drive cars run by electricity(电) .  18 the day will come  19 people will be able to  20 clean air in cities.

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完形填空

　　Clean air  1 important  2 health. If  3 contains(含有) impurities (杂质) ,  4 may  5 by our bodies and make us  6 .

　　We need clean air, but  7 air pollution(污染)  8 generally  9 , especially  10 cities. Now  11 people are  12 the importance  13 clean air. Schools are now teaching about the pollution problem. Industries(工业) are  14 to clean up their smoke. Scientists are  15 to develop  16 engines for cars. Someday we  17 drive cars run by electricity(电) .  18 the day will come  19 people will be able to  20 clean air in cities.

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