________ is known to us all is that the 2012 Olympic Games will take place in London.

A．It B．As C．What D．Which

Professor Wang,together with his colleagues,　　　 working on the project day and night to 　　　　　the deadline.

A.are;meet　　　 B.is;meet　　　　　　 C.are;satisfy　　　　 D.is;satisfy

Though ______, many laws of nature exist.

　 A. not having been discovered 　 B. having not been discovered

　 C. not having discovered 　 D. having not discovered

It usually takes great___________(想象力), warmth and patience to do such a dull job.

He was impolite to the Custom Officer, ____, of course, made things even worse.

A. who　　　　　　 　 B. that　　　　　　 　 C. what　　　　　 D. which

Some children want to challenge themselves by learning a language different from ____ their parents speak at home. A. what　　 B. that　　 C. which　　 D. one

Without your a________________, I couldn’t have succeeded.

He was scolded for not putting the things ____they belonged to．

A．which 　　　　 B．what　　　　 　　　　　　　 C．that　　 D．where

It is my belief ________ we will find a cure for cancer in the next ten years.

A. whether 　　 B. if 　　　 C. that 　　　　 D. which

The two girls are so alike that strangers find ________ difficult to tell one from the other.

A. it　 B. them　 C. her　 D. that