1.作主语：动名词。 如：Teaching is my full-time job. Writing an English composition is not easy. It’s useless taking this kind of medicine. （第三个句子it是形式主语，后面的动名词才是真正的主语）
2.作表语：（1）动名词 My job is teaching. = Teaching is my job. Her full-time job is laying eggs. =Laying eggs is her full-time job.
（2）现在分词 The play is exciting. ≠ Exciting is the play. The story he told us was very interesting. ≠Interesting was the story he told us. 3.作宾语：动名词 I have just finished doing my home work. I suggested asking his brother for some money.
只接动名词作宾语的常见动词有十六个：resist、mind、suggest、delay、keep on ，look forward to、enjoy、include、 appreciate、imagine、practise、finish、succeed in、consider、 can’t help、miss。
4.作宾语补足语：现在分词 I heard the girl singing in the classroom. 5.作定语：现在分词 ⑴动名词作定语表示性质或用途。 a washing machine ＝ a machine for washing a swimming pool ＝ a pool for swimming This is a new washing machine ⑵现在分词作定语表示动作。如果是单词，放在被修饰的名词前；如果是短语，放就放在被修饰的名词之后。 a developing country ＝ a country which is developing a sleeping boy＝ a boy who is sleeping The man talking with my father is Mr. Wang. China is a developing country. 6.作状语：现在分词 现在分词作状语。表时间、原因、条件、结果、伴随（方式）等。 Hearing the cry for help, he rushed out.（时间） Being ill, he went home. （原因）