Training astronauts ______not an easy thing.

Very seldom in my life ________such a thing.A. I have heardB. I heardC. have I h

[单选题]I _____ the wrong thing. Can I use your eraser?A． write B. wrote C. am writing D. will write

The economic recession has indicated that job _ is a rare thing.A. securityB. sa

Fool __________ Jane is, she could not have done such a thing.A. whoB. asC. that

Dont resort to cheap copies ____ for the real thing.A. saveB. save upC. make upD

You __________ all those calculations! We have a computer to do that sort of thi

[单选题]You __________ all those calculations! We have a computer to do that sort o

[单选题]He said he had every( )in his secretary； she would do the right thing.A.wor

[单选题]--How amazing it is that astronauts are exploring outer space!--It’s a challenge, I guess, man against nature.A． of B. for C. by D. about

Why it is unrealistic to send astronauts back to the moon now?A. Because the Whi