It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.
—How many days are there in February?—________thirty days.
Tom is________a common worker. How disappointed his parents are to see he hasn't gained great achievements!
A writer cannot write good works without practice________more than a director can direct excellent plays without experience.
—I'll talk to my son Bill about it as soon as possible. He usually listens.—We need________listening. We need action.
In the dream Peter saw himself________by a fierce wolf, and he woke suddenly with a start.