题目内容
— What are the _______ doing there?
— They are busy _______ their science experiment.
A. Boys students; to do B. Boy students; to do
C. Boys students; doing D. Boy students; doing
【答案】
D
【解析】考查名词复数和非谓语动词的用法。男学生的复数表示为boy students,固定结构“be busy doing sth”忙于做某事。
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