You know, ________ knowledge of ________computer is necessary to a secretary(秘书).
—Has anyone taught him how to do it?—Sure. Lots of advice________, but he hasn’t made a decision.
—The spacecraft has never been to the moon, ________ ? —Certainly.
—Miss Li has taught ____ English for about 3years.—You are lucky. ____ is a very good teacher.
—How long has John been here? — Two years, _______ he still has no friends.
—Excuse me. Could you tell me ________? — Sorry, I am new here.