— 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
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。
— 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
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。