The book written by Gorky is worth __.
| A.read | B.reading | C.being read | D.to read | 
Two people were killed in the serious car _______ the other day.
| A.strike | B.break | C.crash | D.incident | 
It is said that the temperature is unusual mainly _______ global warming caused by human activities.
| A.in spite of | B.by means of | C.in case of | D.on account of | 
The transformation of our city will make _______ for people here to have a comfortable environment.
| A.it possible | B.no possibility | C.impossible | D.there was possibility | 
Mary _______ her mother with the housework, but she didn’t.
| A.must have helped | B.ought to have helped | 
| C.must help | D.should help | 
The local government announced that only when the fire was under control ________ to return to their homes.
| A.the residents would be allowed | B.had the residents been allowed | 
| C.would the residents be allowed | D.the residents had been allowed |