问题
I have tried very hard to work out the problem, but failed. – Why not turn to our monitor for help You see, _______.
A:it never rains but pours
B:it's better to think twice before doing something
C:two heads are better than one
D:a bird in the hand is worth two in the bush;
B:it's better to think twice before doing something
C:two heads are better than one
D:a bird in the hand is worth two in the bush;
正确答案是：
