Today there are more airplanes________ more people than ever before in the skies.

It is snowing outside.Why not close the door to_________ the cold air

It’s quite an informal gathering, you needn’t _____ for it. [ ]

The shoes aren’t _________ for me. I can’t put _________ on.

all ready to put it into operation;__________, we’re going to take action as soon as possible.