Why do English people talk so often about the weather when they start a talk? — Because the weather is a(n) ________ topic (话题).
—Do you have enough men to carry these chairs? —No. I think we need _______ men.
—Could you tell me ______ ?—By watching English movies.
—______to give back the books to the library before Friday.—OK. I will.
As we all know, a dictionary is a book ______ gives the meaning of words.
—Have you known Mr. Smith for a long time?—Yes, since he ______ to our university.