1 . It was not until the entire river was covered with rotten fish which died from acid rain that ____ how serious the pollution was.

A．did the villagers realize	B．made the villagers realize
C．the villagers realized	D．realized the villagers.

2 . It was as a result of his carelessness _______ a serious fire broke out during the night.

A．when

B．that

C．before

D．since

3 . — Today Mary is in low spirits.
— Yes, but she won’t say _______ bothers her.

A．why is it that	B．that is why
C．it is what	D．what it is that

4 . It was in the hotel _____ my father works _____ I met the film star.

A．that; that

B．where; where

C．where; that

D．that; where

5 . It______ we had stayed together for a couple of weeks______ I found we had a lot in common.

A．was until, that	B．was until, when
C．wasn't until, that	D．wasn't until, when

6 . People say, "Guilin's scenery is matchless in the world." It was not until I visited the place _____ I found it really worthy of the reputation.

A．where

B．when

C．that

D．then

7 . It is at Christmas _____ thousands of young people go skiing in the mountain．

A．how

B．which

C．when

D．that

8 . It is because of you______I was blamed by my teacher.

A．because

B．since

C．which

D．that

9 . It is only when people live on à very limited diet_________   it is necessary to make a special effort to supply the missing vitamins.

A．so

B．that

C．since

D．until

10 . It was ________ I got back to my apartment ________ I first came across my new neighbors.

A．what, that

B．what, when

C．when, that

D．that, when