即动词的-ing,-ed短语,可做定语或状语.

The boys tanding by the door is a student.(其中的

standing by the door 就是ing短语做定语修饰boys.)

Knowing the news,he got excited.(knowing the news 短语做状语)

He came into the classroom,followed by two students.(followed by two students.是过去分词做状语)

We met a boy bitten by his father.(bitten by his father是过去分词做定语)