Scientists _______ a lot of experiments on animals, hoping to find and effective way to cure the patients who had AIDS.
#70454
A
carried on
B
carried out
C
carried away
D
carried off
推荐题目
It is uncommon that she is a person ___________up late . 
#73481
A
accustomed to stay
B
accustomed to staying
C
used to stay
D
addicted to stay
What he said at the meeting means _______ those who had cut down the forests. 
#69291
A
to argue against
B
to argue for
C
arguing for
D
arguing against