分词作状语
分词在句中作状语，修饰谓语动词或整个句子，表示动作发生原因、时间、方式、结果、条件、伴随情况等。
分词作状语基本标准
1）分词作状语时，分词逻辑主语必须与句子主语保持一致。2）分词作状语必须和句中主语含有逻辑上主谓或动宾关系，不然不能使用分词作状语。1）Being ill, he didn’t go to school.2) Given much more time, he would do it better.
Eg. Hearing the bell, the students began to enter the classroom. （听见和进入两个动作同时发生）The building being built now is our new library. （being built为现在分词被动形式，表示动作正在进行之中。）
Having done the work, he went home. 完成了工作，他就回家了。