问题补充：
-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. its 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
答案：
A. it never rains but pours
B. its better to think twice before doing something
(答案→)C. two heads are better than one
D. a bird in the hand is worth two in the bush
解析：句意：--我已经尽最大的努力去解决这个问题，但是失败了。--为什么不与我们的班长去帮忙？你明白，人多力量大。分析：对话中一个的经过努力没有解决问题，提出找班长帮助，因此为人多力量大。故选 C
