_____ many times, but he still doesn’t know how to operate the machine properly.
#92970
A
Although I have shown him
B
I have shown him
C
Having been shown
D
Having shown
推荐题目
 Who would you rather ______ the report instead of you?
#94847
A
have write
B
have to write
C
write
D
have written
This is the first time that I        it.
#92693
A
see
B
saw
C
had seen
D
have seen