Question

1. —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

选D boy students, doing
What are the boy students doing there?
翻译：
那些男生同学在那里干什么？
They are busy doing the science experiment.
翻译：
他们正忙着做科学实验。

Answer 2

D
boy 修饰名词时，用单数。be busy doing...忙于....

Answer 3

选择D boy students就如同 girl friends一样的道理，be busy doing sth 固定搭配，表示正在忙。。

Answer 4

D

boy student 的复数是boy students。 be busy doing 是忙于做某事的意思

Answer 5

正确：D boy student的复数形式：boy students; be busy 后接doing.