She ________ speaking in front of many people because she is so shy.

–Has Billy finished his homework today–I have no idea. He ______ it this morning.

Could I watch TV for another while, mum? — Oh, dear, if you ______. [ ]

Don’t you think it necessary that he _______ to Miami but to New York?—- I agree, but the problem is ________ he has refused to.

It is believed that _____ European scientist invented _______.