Since many insects have already become()to
题型:单项选择题
问题:
Since many insects have already become()to DDT, scientists have to look for some new insecticide
A.active
B.resistant
C.tough
D.gradual
Since many insects have already become()to DDT, scientists have to look for some new insecticide
A.active
B.resistant
C.tough
D.gradual