单项选择题
Since many insects have already become（）to DDT, scientists have to look for some new insecticide
A.active
B.resistant
C.tough
D.gradual
点击查看答案&解析
相关考题
-
单项选择题
His parents no longer worry about him. He has a good job and can live（）his own now.
A.at
B.by
C.on
D.with -
单项选择题
He（）the medicine quickly and then drank some orange juice.
A.sucked
B.swallowed
C.licked
D.digested -
单项选择题
While studying he was financially dependent （）his wife.
A.to
B.of
C.on
D.from
