If you want to do the experiment again,you’d better be more careful _______ you made a mistake.?

A. when B. why?

C. where D. that?

If you want to do the experiment again, you'd better be more careful _________ you made a mistake.

1. A.
   why
2. B.
   when
3. C.
   where
4. D.
   that

If you want to do the experiment again, you’d better be more careful ______________________ (你犯过错误的地方) . (where)

23. If you want to do the experiment again, you had better be more careful________ you made a mistake.

A. when     B. why             C. where      D. That