Many a student ______ made that mistake before, which is another way of saying a great many students ________ made that mistake.

The present situation is very complex，so I think it will take me some time to ________ its reality.

The boy         hot on the forehead. He must be sent to the hospital at once.

— We haven’t heard from Jane for a long time.— What do you suppose ______ to her?

—Look！How long________like this?—Three weeks! It's usual here that rain________without 　stopping these days of the year.