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Unit 10 I’ve had this bike for three years. Grammar

现在完成时(三) 含有since和for的现在完成时态   since和for是现在完成时当中常见的...

现在完成时(三) 含有since和for的现在完成时态

 

since和for是现在完成时当中常见的标志词。since“自从……”,for“持续了……”。since用来说明动作的开始时间,for用来说明动作延续的时间长度

考点1  sincefor是现在完成时的重要标志

Something ________ in our hometown since 2014. Now it ________ very modern.

  1. is changed; is looked
  2. has changed; looks
  3. changed; looks

【答案】B

【解析】本题用寻找题眼法。根据since可知第一句用现在完成时;由now可知第二句应用一般现在时。

考点2  sincefor的用法

(1)since的用法

since+过去的时间点。如:年、月、日、几点等

☞since 1990 自从1990年起

☞since 5 o’clock 自从五点起

since+ 时间段+ ago

☞since 3 months ago 自从三个月以前

since+ 一般过去时的从句

☞since you left home 自从你离开家以后

①My grandparents ________ in that city since 2008.

  1. will live     B. live
  2. have lived                              D. were living

【答案】C

【解析】句意:我的祖父母从2008年就生活在哪个城市里。since+过去的时间点是现在完成时的标志。

②I'm looking after Tom today. He's been in my house ________ 8:00 this morning.

  1. at B. since                    C. for              D. till

【答案】B

【解析】句意:我今天一直在家照看汤姆。从今天早上8点钟起他就一直在我家了。8:00 this morning是一个过去的时间点。since后接过去的时间点表示过去的动作延续至今,用于现在完成时态。

(2)since的一个固定句式“It is+时间段+since+一般过去时的从句”。

It is five years since I came here. 我来这儿5年了。

(3)for的用法:for+时间段

—Did you see Tom yesterday?

—No,I ________ him for a long time.

  1. didn't see      B. hasn't seen
  2. saw                  D. haven't seen

【答案】D

【解析】本题用寻找题眼法。根据for a long time可知用现在完成时,且主语是第一人称,故用助动词have。

(4)在现在完成时当中,若对since和for引导的时间状语进行提问,都可以用how long来提问。

—________ have you lived in Lanzhou?

—Since my parents found jobs here.

  1. How long    B. How far
  2. How soon                          D. How old

【答案】A

【解析】考查how词组辨析。how long多久,提问时间段;how far多远,提问距离;how soon多久以后,提问将来的时间,答语常用in+一段时间;how old多大,提问年龄。根据答语可知,问句是对时间段提问。

(5)since和for的句式转换:

since+时间段+ago=for+时间段

They haven't changed since twenty years ago.

=They haven't changed for twenty years.

他们已经二十年没有改变了。

考点3  延续性动词、短暂性动词与since, for

       延续性动词表示能够延续的动作。短暂性动词表示不能延续的动作,这种动作发生后立即结束。

(1) 若现在完成时的句子中含表示时间段的时间状语(如含since/for引导的时间状语),则谓语只能使用延续性动词。

—The boy misses his parents very much.

—So he does. They ________ the hometown for nearly two years.

  1. have left     B. will leave                        C. have been away from

【答案】C

【解析】由for nearly two years可知用现在完成时态;动词leave是非延续性动词,在完成时中要转换为be away from。

(2) 短暂性动词可以转化为延续性动词

①直接换成延续性动词

buy买→have有                                            borrow借→keep保留

put on穿上→wear穿着                                          come/go/become来/去/变成→be在/是

②转换成be+名词

join the army参军→be a soldier当兵                join the Party 入党→be a

Party member成为一名党员                                   go to school去上学→be a student成为一名学生

③转换成be+形容词/副词

die死亡→be dead死了                                    finish结束→be over结束

begin开始→be on 在上映/已开始                           leave离开→be away远离的

fall asleep入睡→be asleep睡着的                            close关闭→be closed关着的

④转换成be+介词短语

go to school去上学→be in school在上学

join the army参军→be in the army在军队中

Her son ________the army for two months. She misses him very much.

  1. has joined     B. has been in
  2. joined           D. was in

【答案】B

【解析】本题用寻找题眼法。该句中“for two months”为持续性时间状语,故要把非延续性动词转换成延续性动词。join应该转换成be in/ be a member of,其现在完成时结构为has/ have been in或has/ have been a member of。

考点4  现在完成时和一般过去时的转换

由延续性动词构成的现在完成时的句子可与由非延续性动词构成的句子相互转换。

I have kept the book for five days.

=I borrowed the book five days ago.

我五天前借的这本书。

Mary came to China three years ago.(改为同义句)

Mary ________ ________ in China since three years ago.

【答案】has been

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