____some doubt among scientists about the cause of cancer.
#92930
A
It exists
B
There exists
C
There is existing
D
It is existing
推荐题目
_____ is little doubt that the Chinese women basketball team will beat the Japanese team.
#94838
A
It
B
That
C
There
D
Which
----Is it the first time you _______ Beijing?----No. But the first time I ______ here, the city wasn’t so beautiful.
#92535
A
visited; came
B
visited; have come
C
have visited; have come
D
have visited; came
As we all know，dark glasses can ________ the eyes from strong sunlight.
#92444
A
prevent
B
care
C
help
D
protect
Before he went abroad, he spent as much time as he ____ English.
#94791
A
could learning
B
learned
C
to learn
D
could learn