单项选择题
Nobody can do two things well()
A.at one time B.at once C.one time D.once
单项选择题 May I speak to your manager Mr. Williams at five o'clockI'm sorry. Mr. Williams()to a conference long before then.
单项选择题 We can't be delayed(). We must hurry.
单项选择题 I'm glad to say that he's already finished()50% of the book in these past three days.