Although the causes of cancer ________, we do not yet have any practical way to prevent it．
#103264
A
have uncovered
B
have been uncovering
C
are uncovering
D
are being uncovered
推荐题目
The violin will have to be tuned before it _____.
#103337
A
plays
B
should play
C
is played
D
is being played
Using a telescope we could see that something .
#102178
A
is happening
B
happened
C
would happen
D
was happening
Since the project has been ___ on well, you must ___ it on until it is completed.
#101519
A
carrying, carry
B
going, carry
C
going, go
D
carrying, go
— What do you want for breakfast, Joe? — I think I _______ some bread and milk.
#99657
A
will have
B
am going to have
C
had
D
am having
---When are you going to travel to Beijing? ---The train ______ at six tomorrow morning, and I _______ for the station at four o’clock.
#101339
A
leaves, leaves
B
is going to leave, am going to leave
C
is going to leave, leaves
D
leaves, am going to leave