---There is somebody knocking at the door. Who________ it be?---I’m not sure. It ________ be a postman.
While the boy ______ down the street, the UFO _____ .
I can’t believe _____ a little girl can read _____ many books.
---Could you tell us ______? ---In two days.
--- Are you free today, Mrs Green? --- I’m free every day ______ today.
They want to make more cars with ____ workers and ____ money.I think it’s impossible.