of是介詞，一般后接名詞，代詞或動名詞。for同樣是介詞，后接名詞，代詞或動名詞。意義多為“為了”。

　　1、Would you say what you felt was a feeling of betrayal?

　　你是否覺得有一種被人出賣的感覺？

　　2、A flock of birds flew towards us slowly from far away.

　　一群鳥兒從遠處朝我們緩緩飛來。

　　3、We could all do with a cup of tea .

　　要是能給我們都來杯茶就好了。

　　4、Isn't that enough for you?

　　那對你來說不夠嗎？

　　5、I knew he worked for a security firm.

　　我知道他在一家保安公司工作。

　　6、She appears nightly on the television news, speaking for the State Department.

　　她作為國務院的發言人，每晚都會出現在電視新聞中。