——The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?
——____ Tom have a try?
| A．Shall | B．Can | C．Will | D．Need |
---I called you last night, but nobody answered.
---Oh, I usually___off my cellphone by 9:00 p.m.
| A．switched | B．have switched | C．switch | D．had switched |
---You aren’t looking well. Anything the matter?
---I’ve been surfing the net too long. I’m a bit tired.I can hold on,____.
| A．though | B．yet | C．besides | D．therefore |
All of the things there are inexpensive, with prices ________ from about $1 to $10.
| A．ranging | B．changing | C．distinguishing | D．differing |
the sentence , so he asked the teacher to explain it again.
| A．Not having understood | B．As he didn’t understand |
| C．Having not understood | D．He didn’t understand |
——The weather is too cold ____ March this year.
——It was still ____ when I came here years ago.
| A．for; colder | B．in; cold | C．in; hot | D．for; hotter |