单项选择题A．He must hand in a full report on the exhibition.B．He is too busy to go along.C．He has to wash his hands first.D．He has already seen the show.

单项选择题A．The library no longer had the book on reserve.B．The library closed earlier than he’ d expected.C．The professor had chosen a mystery book for him instead.D．The homework assignment isn’t clear.