用法
a.表示現在(指說話人說話時)正在發生的事情。
We are waiting for you.
b.習慣進行：表示長期的或重復性的動作，說話時動作未必正在進行。
Mr. Green is writing another novel.
（說話時并未在寫，只處于寫作的狀態。)
c.表示漸變的動詞有：get，grow，become，turn，run，go，begins等。
d.與always，constantly，forever等詞連用，表示反復發生的動作或持續存在的狀態，往往帶有說話人的主觀色彩。
動詞ing形式變化規則
1.–ing分詞的構成主動形式 被動形式 doing being done 一般式 完成式 having done having been done 否定式：not+--ing/not having(been) done 不是 having not (been) done。
2.一般式和完成式的用法--ing分詞的一般式表示和謂語動詞所表示的動作同時進行的一個動作；完成式表示先于謂語動詞動作之前的一個動作。如： Walking along the street, he caught sight of an old friend of his. Not having studied his lessons very hard, he failed the examinations.
3.---ing分詞的被動式當－ing分詞與它的邏輯主語構成被動關系時，需要用被動形式。根據－ing 分詞動作發生的時間，－ing分詞的被動式分為一般被動式(being done)和完成被動式(having been done),如：The question being discussed is very important. Having been praised by the teacher, he works even harder.
4.---ing分詞的句法功能1)---ing分詞作主語 Learning English has become a part of his life. It is no use trying to repair the ship. These holes are much too big. 2) ---ing分詞作賓語 以下動詞必須跟---ing分詞作賓語：admit/ appreciate/avoid/consider/delay/deny/dislike/enjoy /excuse/finish/image/keep/mind/ miss/postpone/put off/practise/risk/stand/ stop/ suggest / give up/cannot help。