Mr. Wu___this math problem____him many times, but he still doesn’t understand it.
#38768
A
explains ; to
B
has explained ; for
C
has explained ; to
D
explained ; with
推荐题目
_____ when the light went on last night?
#37783
A
What were you doing
B
What have you done
C
What did you do
D
How were you doing
In recent years, the economy of our country _________ rapidly.
#39782
A
is increased
B
has increased
C
increased
D
has been increased