题目内容：

it is unwise ______down his request to be admitted into the culb
A for they to turn B for them to turn C of them to trun D for their turning 这里 能否解释下为什么 不选其余的选项 而是C

优质解答

It‘s +adj.（形容词）for sb to do sth 对某人来说做某事是.
这是固定句型