________ several times，but he still doesn't know how to do it correctly.
#30467
A
Although I've taught him
B
I've taught him
C
Having been taught
D
Having taught
推荐题目
… Will you go to the meeting for their discussion? … No, ______ invited. I don’t feel like getting involved in their business.
#30639
A
unless
B
until
C
even if
D
otherwise
I was feeling left out in the new school Alice ,an easygoing girl from Canada ,came to stay with me．
#30187
A
if
B
once
C
when
D
unless
—Why didn’t you tell him about the meeting?—He rushed out of the room _____ I could say a word.
#79828
A
before
B
until
C
when
D
after
—We’re supposed to be there at 6:00?—_______ I know.
#80103
A
As soon as
B
As far as
C
So long as
D
As possible as
It's really very dangerous.One more step，________ the baby will fall into the well.
#30469
A
or
B
so
C
but
D
and