Perhaps the day will come _____ people will be able to breathe clean air in cities.
举一反三
- Perhaps the day will come _____ people will be able to breathe clean air in cities. A: when B: while C: as D: since
- 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
- Most cities in the country have introduced "Clean Air Zones" _____ factories and households are only allowed to burn smokeless fuel.
- One day people will be able to go to the moon ____________ holiday.