—Did you find the missing couple in the mountain yesterday?—No, but we ______ to get in touch with them ever since.
#100903
A
had tried
B
have tried
C
have been trying
D
had been trying
推荐题目
Take care! Don’t drop ink on your shirt, for it _______ easily.
#99906
A
won’t wash out
B
won’t be washed out
C
isn’t washed out
D
isn’t washing out
They _________ on the program for almost one week before I joined them, and now we are still working on it as no good results have come out so far.
#103812
A
have worked
B
had worked
C
have been working
D
had been working
Once new difficulties _________ in your work, it’s always important to use your brains．
#101546
A
raise
B
arise
C
arouse
D
rise
The vegetables didn’t taste very good. They _______ too long.
#100525
A
had been cooked
B
were cooked
C
have cooked
D
cooked
With the help of high technology, more and more new substances ___in the past few years.
#101737
A
discovered
B
have discovered
C
had been discovered
D
have been discovered