—Is Jack on duty today? —It ______ be him. It is his turn tomorrow.

--- Will you take up teaching as a career after graduation? --- Hard to say. I _______ go abroad for higher education instead.

— Hello, may I speak to Mr. Wu? — I’m afraid he is not in now. ______ I take a message?

— I haven’t got the reference book yet, but I’ll have a test on the subject next month. — Don’t worry. You ________ have it by Friday.

— What does the sign over there say?— No person ______ enter the area without the official permission.