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

I was on the highway when this car went past followed by a police car. They ______ at least 150 kilometers an hour.

You had better not keep the window open , ____ ? 

It’s required that the students___ mobile phones in their school, so seldom ____ them using one.   

This is his only request that the room ______ after being used.