after幾種用法：
一、after作介詞的用法：
1.after+名詞，作為介賓短語(yǔ)，
如：after 5 o'clock。五點(diǎn)以后。
He ran after the bus.他在那輛公交車后追著跑。
2.after+動(dòng)名詞，也是作為介賓短語(yǔ)，
如：after having finished my homework。完成我的作業(yè)后。
I will go to bed after drinking the milk.
3.after+代詞，作為賓語(yǔ)的主語(yǔ)，
如：He went home after he finished all the work
二、after做副詞的用法：
如：three hours after三小時(shí)后; He told me after that he had not enjoyed the film.他告訴我后來他一點(diǎn)都不想看電影。
三、after做連詞的用法：
如：I saw them after I arrived.我到了之后才看到他們。
用作連詞引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)注意：若主句用將來時(shí)態(tài)(或含有將來意味)，則時(shí)間狀語(yǔ)從句要用一般現(xiàn)在時(shí)態(tài) (表將來意義)表將來意義，而不能直接使用將來時(shí)態(tài)：他回來后我就走。正：I’ll leave after he comes back.誤：I’ll leave after he will come back.
after前后時(shí)態(tài)
1、遵循“主將從現(xiàn)”原則。
如：He will go to Beijing to work after he graduates from the university.
他大學(xué)畢業(yè)后將去北京工作。
2、從句表示的動(dòng)作發(fā)生在主句動(dòng)作之前，如果強(qiáng)調(diào)從句的動(dòng)作發(fā)生在前，從句謂語(yǔ)要用過去完成時(shí)，主句用一般過去時(shí)。
如：He went out for a walk after he had finished the work.
他完成這項(xiàng)工作后他出去散步。
3、從句表示的動(dòng)作發(fā)生在主句動(dòng)作之前，如不強(qiáng)調(diào)動(dòng)作的先后，主句和從句均用一般過去時(shí)。
如：He went to bed after he finished his homework last night.
昨晚他完成作業(yè)后上床睡覺。