Question

高中英语问题求解！

The naughty boy always pretends to be busy doing his homework ________ his father enters his room to see what he's doing alone.
A.while
B.as
C.each time
D.once

Answer 1

选C
首先AB 就被排除了，因为when=as 后面都是要加段时间的，而enter明显是一个瞬间动词不能与when / as连用，再就有once 主意不符，所以就只有正确答案C.

Each time something bad happens, I can choose to be a victim or choose to learn from it.

每次有什么坏事发生时，我可以选择作为一个牺牲者或者从中吸取教训。

Answer 2

B。as有时可当作when

Answer 3

选A

Answer 4

选a