现在完成时是初中英语语法的重点之一。它表示过去发生的某一动作或存在的状态，一直持续到现在，并可以和以for或since引导的表示一段时间的状语连用，也可以用在以“how long”提问的句子中，句子中的谓语动词一般为延续性动词。但是，有些动词所表示的动作是短暂的，这类动词叫做非延续性动词。如：come, go, reach, arrive, leave, borrow, buy, join, die, begin, start, finish等。在现在完成时的句子中，非延续性动词作谓语动词时，不能和表示一段时间的状语连用。
　　 同学们在使用这两类动词作谓语动词时，常会出现错误。例如：
　　 （误）Tom has bought the book for a week.
　　 （正）Tom has had the book for a week.
　　 （误）My father had joined the Party for ten years.
　　 （正）My father has been in the Party for ten years.
　　 如果要表示动作的连续性，就要把非延续性动词转换成相应的延续性动词或短语，具体转换如下：
　　come/go/reach/arrive→be in/at, leave→be away from, borrow→keep, buy→have, join→be in/be a member of, die→be dead, start/begin→be on, finish/end→be over, open→be open (adj.), close→be closed (adj.), marry→be married
　　
　　注意：
　　 1. 非延续性动词可以在现在完成时的否定句中作谓语，并可以与for，since引导的时间状语连用，表示动作的延续过程。例如：
　　 She hasn’t bought any new clothes since last year.
　　 2. 在现在完成时的肯定句中，非延续性动词作谓语时不能与for，since引导的表示一段时间的状语连用，但可以用其他句式来表示同一个意思。例如：
　　 He has been away from Beijing for two years.
　　 = He left Beijing two years ago.
　　 = It is two years since he left Beijing.
　　 = Two years has passed since he left Beijing.
　　 练习：用现在完成时改写下列句子，使A，B两句意思基本一致。每空限填一词。
　　 1. A. They came to our school in 1980.
　　 B. They ____ ____ ____ our school since 1980.
　　 2. A. The man died five years ago.
　　 B. The man ____ ____ ____ for five years.
　　 3. A. The meeting began two minutes ago.
　　 B. The meeting ____ ____ ____ for two minutes.
　　 4. A. We borrowed two books last week.
　　 B. We ____ ____ the two books for a week.
　　 5. A. When did the train arrive here?
　　 B. How long ____ the train ____ here?
　　编辑/丁俊玲