it′s very nice of you to help me find the key { }the door .A;of B;for C;to求详解

问题描述:

it′s very nice of you to help me find the key { }the door .A;of B;for C;to求详解

C
THE KEY TO THE DOOR是固定用法.这里to是做的所有格.相当于's
部分名词的所有格不用's 或 of +名词来表示,而是用 to 表示.
有钥匙,答案,桥,路,出口,入口.这些的所有格要用to