.分词
1.只有现在分词才有时态和语态形式的变化.现在分词的时态、语态有两种形式：①一般式,如,doing / being done;
②完成式,如,having done / having been done .
2.基本用法
①现在分词的一般式,表示的动作与谓语动词表示的动作同时发生,或在谓语动词表示的动作之前发生.如：
The boys and girls went to school,singing and dancing all along the way .
They all jumped with joy ,hearing the good news.
The girl could not help crying ,being criticized in the public.
②现在分词的完成式,表示的动作在谓语动词表示的动作之前已发生,常用作时间状语或原因状语.如：
Having done the work very well ,he was praised by the teacher.
Having been shot by a bullet,the man fell down dead.