________ 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
__________ you promise to come to help me,I don’t mind what time tomorrow you arrive at my place.
#80081
A
So long as
B
So far as
C
As good as
D
As well as
Doctor Smith has made another wonderful discovery, _______ great importance.
#30394
A
which I think is of
B
which I think it is of
C
which is I think
D
I think which is
---Did you meet with the famous space hero, Yang Liwei?---_____ I had come here earlier.
#33990
A
If only
B
Only if
C
But for
D
Despite
-–Do you think he will make a good teacher?--Yes, I believe he is ________ any good teacher.
#31409
A
as patient and devoted a man as
B
so patient and devoted a man as
C
a man as patient and devoted
D
such a patient and devoted man