B 1.Be busy (in) doing sth ,忙于做某事 2. prepare for 是固定词组，为...做准备 3.prepare用作不及物动词时：prepare for sth.表示"为......做准备"。 prepare用作及物动词时：. prepare sth.表示"准备......"，后接名词或代词作宾语。举例：Our English teacher was preparing the lessons when I came into the office.我进办公室时，我们的英语老师在备课。The students are busy preparing for the final exam.学生们正在准备期末考试。还有问题吗？
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