Pollution is a serious problem. Scientists have _______ some good ways to save it.
#55161
A
come up with
B
come on
C
come out
D
come up
推荐题目
I enjoy reading the novel that was written by Zhang Ailing.
#51938
A
written
B
writing
C
wrote
D
writes
Grandmother always her children when she feels sad.
#59150
A
thinks over
B
thinks about
C
thinks of
D
thinks out