Oxygen is a kind of gas, ______we couldn’t live.

A. without it    B. without that    C. without which    D.  if not

She wrote a letter to her father, ______she made her secret known.

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

China has hundreds of islands, ______we all know.

A. in which    B. at which   C. of which    D.  which

Rober is good at language, ______we all know.

A. because  B. for  C. as  D.  since

Don’t do such things _____you are not sure about.

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

The professor has two sons, _____are teaching in the same university.

A. neither of them   B. either of them  C. both of them   D.  both of whom

Don’t trust such men ______overpraise you to your face.

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

The factory ______I am going to is the place _____my mother used to work many years ago.

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

The Summer Palace is one of the most beautiful parks ______built in the Qing Dynasty.

A. where were  B. where was   C. that were   D.  which was

The last river _____they crossed is two miles wide.

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