Do you know where David is ? I couldn’t find him anywhere. — Well. He ______ have gone far –his coat’s still here.

It is required that all traffic participants should___the traffic rules to make traffic safer and faster．

How was your holiday — Itcouldn’t have been _____ I just stayed in the hotel because it was rainingmost of the time

I’m too nervous to give a talk before so many people．— _____________, Maria．You can do it．

The students listened carefully and ____ what their teacher said.