本文目录
英语中的完成时主要分为现在完成时、过去完成时和将来完成时三种。使用完成时可以表达某个动作已经完成或者对过去的事情产生影响。那么，完成时具体在哪些情况下使用呢？
现在完成时
现在完成时用于表达过去某一时刻开始的动作一直持续到现在或者刚刚结束的情况。比如：
- I have lived in this city for three years. (我已经在这个城市住了三年了。)
- She has just finished her homework. (她刚刚完成了她的作业。)
- They have known each other since high school. (他们从高中开始就认识了。)
过去完成时
过去完成时用于表达过去某一时刻或事件之前已经完成的动作。比如：
- By the time I arrived at the party, everyone had already left. (当我到达聚会现场的时候，每个人都已经离开了。)
- He had studied English for five years before he went to America. (他去美国之前已经学了五年的英语。)
- She had never been to the beach until last summer. (去年夏天之前她从未去过海滩。)
将来完成时
将来完成时用于表达将来某一时刻之前已经完成的动作。比如：
- By this time next year, I will have graduated from college. (明年这个时候，我将已经从大学毕业了。)
- They will have been married for 10 years by the end of this month. (到本月底，他们将已经结婚十年了。)
- I will have finished my project before the deadline. (我将在截止日期之前完成我的项目。)
综上所述，完成时在英语中有着广泛的应用。掌握好各种完成时的用法，可以更加准确地表达自己的意思，提高英语表达能力。
