______ is natural, he married Mary.

A It B What C Which D As

 His father died last year, ______ made it impossible for him to go abroad
A when   B which   C as   D that

He must be from Africa, ______ can be seen from his skin.
A that B as C it D what

The reason ______ he didn’t come was __ he was injured.
A.that, because　B. why, that C.why, because D. that, that

Can you solve such problems ______ raised by the audience?
A what were 　 　 B as were C that were D which were

I have bought the same dress ______ she is wearing.
A as B that C which 　 D than

 Is it in that factory ______ “Red Flag” cars are made?
A in which B where  C that    D which

 This is the very place ______ I’m wishing to live in
A where   B which  C that  D in which

He has left Beijing, ______ a meeting is to be held.
A when B where　C as D which

 Have you ever been to Shanghai, ______ I left ten years ago?
A where  B which   C that   D when