--Tom has won the first prize in the singing contest of our school.-- .You see

----- Tom has won the first prize in the singing contest of our school.
------- .You see he always works hardest.
A. He is a lucky dog
B. No pains , no gains
C. All roads lead to Rome
D. It is no use reasoning with a fool.

A. He is a lucky dog (答案→)B. No pains , no gains C. All roads lead to Rome D. It is no use reasoning with a fool.解析：考查交际用语：A．He is a lucky dog他很幸运，B. No pains , no gains不劳无获C. All roads lead to Rome条条大路通罗马D. It is no use reasoning with a fool.不可理喻。句意：--汤姆在我们学校的歌唱比赛中获得一等奖。---不劳无获，你看他总是最努力的。选B。

就是这个解释