Stone seldom refuses to help others when they turn to him for he is only too ready to

问题补充：

Stone seldom, , refuses to help others when they turn to him, for he is only too ready to do so.

A. if never

B. if not

C. if ever

D. if any

答案：

A. if never

B. if not

(答案→)C. if ever

D. if any

解析：考查省略句。If not如果不；if any如果有一些；If ever如果曾经有过…=if Stone has ever refused to help others.句意：当别人想Stone求助的时候，他很少拒绝。因为他是一个乐于助人的人。故C正确。