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Unit 8
现在完成时（二）
知识点1. for和since在现在完成时中的应用
（1）在表示行为或状态从过去一直持续到现在时，通常要与表示一段时间的时间状语连
用，这类状语通常由for或since引导。for后接一段时间，如for five years；而since后多
接时间点，如since January 2020。
They have had the cat since they got married. 他们自结婚以来就一直养着这只猫。
They have been married for 20 years. 他们已经结婚20年了。
（2）“since+时间点”和“for+时间段”常作现在完成时的标志。两者之间常可以进行同
义转换。
Chen Xiao has dreamed of being a biologist since eight years ago. = Chen Xiao has
dreamed of being a biologist for eight years. 陈笑八年前就梦想成为一名生物学家。
（3）对现在完成时的时间状语进行提问时，常用how long。
How long have you been like this? 你这个样子有多久了？
How long have you played tennis? 你打网球打了多长时间了？
知识点2. 非延续性动词与延续性动词之间的转换
（1）在现在完成时的句子中，表示持续的动作或状态时，常用延续性动词与表示时间段的
时间状语连用。
I have played the guitar for six years. 我弹吉他六年了。
（2）与表示一段时间的时间状语连用时，应将非延续性动词转换为延续性动词或表示状态
的短语等。
I borrowed this magazine three months ago. 我三个月前借了这本杂志。
I have kept this magazine for three months. 这本杂志我已经借来三个月了。
（3）常见的非延续性动词转换为延续性动词的情况:
①用与其意义相对应的“be+形容词/副词/介词/名词等”结构。
非延续性动词结构
Leave → be away begin/start → be on
join → be in/a member (of) die → be dead
open → be open
I joined the club two years ago. 我两年前加入的这个俱乐部。→ I have been in/a member of the club for two years. 我加入这个俱乐部两年了。
②用与其意义相对应的延续性动词。
非延续性动词 延续性动词
buy have
borrow keep
put on wear
I bought this pop-up book about the Palace Museum one week ago.
我一周前买了这本关于故宫博物院的立体书。
→ I have had this pop-up book about the Palace Museum for one week.
我买来这本关于故宫博物院的立体书已经一周了。
