1、after后面直接加一个动词时，它是作为一个介词，动词用ing形式。
2、after是引导一个从句，从句是一个独立完整的句子，可以用各种时态和语态。
3、after做介词时，后面只能加名词/代词/动名词短语(doing sth)，形成介宾短语，做句子的状语(时间状语/地点状语)。
4、after做连词时，引导一个时间状语从句，意思是“在...之后”。
拓展资料
after
1. No matter where you go in life or how old you get, there's always something new to learn about. After all, life is full of surprises.
不管你生活在哪里，你有多少岁，总有新东西要学习，毕竟，生活总是充满惊喜。
2. He was fired from his job after roughing up a colleague.
他因为对一位同事动粗而被开除了。
3. The mystery hero imme-diately alerted police after spotting a bomb.
那个无名英雄发现炸弹后马上报了警。
4. After a three-weekend courtship, Pamela accepted Randolph's proposal of marriage.
经过3个周末的追求之后，帕梅拉接受了伦道夫的求婚。
5. The ballot was re-run on Mr Todd's insistence after accusations of malpractice.
因被控舞弊，在托德先生的坚持下重新进行了投票。
6. He does deserve some good luck after so much wretchedness.
经过这么多苦难之后，他应该行点好运了。
7. After sixteen years of marriage they have grown bored with each other.
结婚16年后，他们已经渐渐彼此厌倦了。
8. After years of neglect and decline the city was cleaning itself up.
多年的玩忽职守和经济萧条过后，这个城市在进行自我整顿。
9. After his elevation to the papacy, he reigned for two years.
他升任教皇后在位两年。
10. She dropped out after 20 kilometres with stomach trouble.
20公里后她因胃痛而退出了比赛。
