The math problem seems very easy, but in
题型:选择题
问题:
The math problem seems very easy, but in fact it is very difficult_______.
A.to work out
B.being worked out
C.working out
D.to be worked out.
The math problem seems very easy, but in fact it is very difficult_______.
A.to work out
B.being worked out
C.working out
D.to be worked out.