It’s necessary _____ us _____blind people cross the street.[ ]

The boy was able to __________ himself when he was very young.

Tom, you are going to buy a new flat here, aren’t you?— Yes, but I can’t _____an expensive one.

There _______ a number of volunteers in the club and the number of them _______ growing larger and larger.

Sir, you ______ be sitting in this waiting room. It is for women and children only.