1.定语:介词短语作定语通常放在被修饰的名词或代词之后. 如:You must know the meaning of every word you learn. (修饰the meaning)

2.状语:用来修饰动词、形容词、副词或整个句子、 如:Ships are built for sea transport. (修饰谓语动词are built)

3.表语:介词短语有时可放在系动词后作表语. 如:These goods are of perfect quality.

4.宾(主)语补足语:介词短语有时可作宾语补足语和主语补足语.