Perhaps the day will come _____ people will be able to breathe clean air in cities.
A: when
B: while
C: as
D: since
A: when
B: while
C: as
D: since
举一反三
- Perhaps the day will come _____ people will be able to breathe clean air in cities.
- How many cities<br/>will have air quality monitoring systems installed by the end of this<br/>year?() A: 42 cities. B: 220 cities. C: 150 cities. D: 262 cities.
- Generally speaking, the people in ________are more polite . A: poor cities B: prosperous cities C: underdeveloped cities D: clean cities
- The day will surely come when all the people in the world enjoy peace.( )
- The day will come ____________ peace-loving people enjoy a world without war. (when; but)