The scientists are studying the effects of human activities______the environment.
#29004
A
in
B
at
C
on
D
with
推荐题目
I’ll be free ___ seven o’clock.
#28796
A
after
B
on
C
in
D
at
Which book is much better      quality?
#26585
A
In need of
B
in case of
C
in terms of
D
in favor of
It is amazing that the little boy can swim ________the river ________100 meters in width. 
#25840
A
across; measuring
B
over; measured
C
across; measure
D
through; measuring