In much of the animal world, night is the time ____ for sleep —pure and simple.
| A．set aside | B．set down | C．set off | D．set up |
You're the only person ______I've ever met ______could do it.
| A．who;/ | B．/; whom | C．whom;/ | D．/; who |
.In our factory there are 2,000 workers, two thirds of ____are women.
| A．them | B．which | C．whom | D．who |
The letter is from my sister, ______is working in Beijing.
| A．which | B．that | C．whom | D．who |
—I‘d like a pen which _________ well.
—Will this one _________?
| A．writes； do | B．writes； work |
| C．is written； do | D．is written；work |
It was not until liberation that _________ to his hometown.
| A．did he return | B．was he returned |
| C．he did return | D．he returned |