例句：

　　As it happens, I have a spare set of keys in my office. 碰巧我在辦公室有一套備用鑰匙。

　　My mom gave me a set of keys. 我媽媽給了我一串鑰匙。

　　A set of keys is on the desk. 有串鑰匙在桌子上。

　　Stranger: Excuse me, did you see a set of keys? 陌生人：你好，你看到一串鑰匙了嗎?