In order to keep the balance of ecosystem, every possible means _______to deal with the problems of the over-exploiting of natural resources.
#101293
A
has tried
B
has been tried
C
have taken
D
have been taken
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Although medical science __________ control over several diseases,what worries us is that some of them are returning.
#99526
A
achieved
B
has achieved
C
will achieve
D
had achieved
—I am searching one online shopping site after another for a computer. —So __________I before I decided to buy a new camera.
#102739
A
had
B
have
C
am
D
would
All possible means ___ been tried to stop the air______.
#103381
A
has, polluted
B
have, polluting
C
have, being polluted
D
has, being polluted
Long ago, the CLA and other US intelligence officials concluded that Bin Laden _____ the day –today leader of the terrorist organization he founded over 10 years ago.
#104975
A
was stopped being
B
had stopped to be
C
have stopped being
D
had stopped being
He ______ quite well, but he hasn’t had time to swim since this summer.
#104118
A
will swim
B
Have swum
C
swam
D
swims