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
---We've spent too much money recently.---Well，it isn't surprising. Our friends and relatives ______ around all the time.
#100617
A
are coming
B
had come
C
were coming
D
have been coming
Amy insists that she ____ the secret to lose weight. But she won’t share it with us.
#101092
A
had discovered
B
discovers
C
has discovered
D
will discover
I____ her to work hard at English, but she didn’t listen to me.
#102560
A
persuaded
B
tried to persuade
C
managed to persuade
D
suggested
As she _____ the newspaper, Granny _____ asleep.
#104166
A
read ; was falling
B
was reading; fell
C
was reading; was falling
D
read; fell
He ______ a book about his adventures in Tibet. I hope he can find a good publisher when it is finished.
#99824
A
was writing
B
wrote
C
has already written
D
is currently writing