Loulan is believed __________ over by sandstorms gradually from AD200 to AD400.
#92411
A
to cover
B
to be covered
C
to have covered
D
to have been covered
推荐题目
Before he went abroad, he spent as much time as he ____ English. 
#94791
A
could learning
B
learned
C
to learn
D
could learn
-----Was the class long enough?-----No, _______ enough.
#94703
A
it wasn’t much too long
B
it wasn’t too much long
C
it wasn’t quite long  
D
it wasn’t too long much
The scientist has made quite a few discoveries, ______ of great importance to the whole world.
#95024
A
which I think they are
B
which I think are
C
I think which are
D
that I think they are