1 . 他突然意识到照片中的其他中国人不关心他们的同胞发生了什么事情。（运用it作形式主语）
______________________ the other Chinese men in the photo apparently did not care about what was happening to their fellow countrymen.

2 . It’s a challenge for me to ______ (memory) 50 new words per day. （所给词的适当形式填空）

4 . ________is very dangerous to ________these viruses without any protection.

A．That; expose to

B．That; be exposed to

C．It; expose to

D．It; be exposed to

5 . ________ worried me that my mother’s eyesight was declining. (用适当的词填空)

6 . ________________(据说) we’ll have to do extra work on Sunday. (根据汉语提示完成句子)

7 . __________ annoyed him most that he had received no apology.

A．It

B．How

C．What

D．Which

9 . ______ is acknowledged to us all that the old scientist, for whom life was hard in the past, still works hard in his eighties. (用适当的词填空)