Question

【题目】— 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

Answer 1

【答案】D

【解析】

句意：—男学生们在那儿干什么？—他们正忙于他们的科学实验。boy students是boy student的复数形式。be busy doing sth.忙于做某事,do-doing。故答案为：D。