— What are the _______ doing there? — Th
题型:选择题
问题:
— 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
— 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