G:現在完成時棗表示到目前為止已經完成，并對現在留下某種后果和影響的動作。
結構：助動詞have/has + 動詞的過去分詞
用法:
1.表示過去發生的某一動作對現在造成的影響或結果,常與一些時間狀語,如:already, yet, ever, never, just, before, once,twice等連用,也可以和包括現在在內的時間狀語,如these days,today,this year,so far等連用.eg.I have already posted the letter. (信已經不在我這兒了)
2.表示過去發生的動作或存在的狀態,一直持續到現在,也許還將繼續下去,可以和表示從過去某一時刻延續到現在的一段時間的狀語連用,即for +時間段,since+時間點/從句, in the last ten years等,謂語只可用延續性動詞.
解析： 1.英語動詞根據詞義可分為兩種,一種是延續性的,一種是終止性的,終止性動詞(也可稱為非延續性動詞,瞬間動詞,或點動詞),如begin,start,die,buy,leave, come等,表示動作的發生與結束于一瞬間完成,不能再延續,所以它的現在完成時不能和表示延續的時間狀語連用,即不能與表示一段時間的狀語,for+時間段, since+時間點/從句連用,也不能用在how long引導的特殊疑問句中.
eg. I’ve left Shanghai for three days.(×) I’ve been away from Shanghai for three days.( √ ).
I left Shanghai three days ago. ( √ ) It is /has been three days since I left Shanghai.( √ )
2.初中英語課本中常見終止性動詞有:leave, go, come, arrive, begin, buy, borrow, die, join, become等.終止性動詞要表示持續時, 可用以下方法:
⑴.將時間狀語改為時間段 + ago,句中謂語動詞用一般過去時.
eg.我弟弟參軍兩年了. My brother joined the army two years ago.
⑵.若保留for+時間段,since+時間點/從句, 或用在 how long 句型中,則需將終止性動詞改為相應的狀態動詞或延續性動詞
常見終止性動詞與延續性動詞(或狀態動詞)的對應關系如下
come/go/arrive/get/reach/move------be in/at open-----be open
die------be dead close----be closed become---be borrow---keep begin/start-----be on put on----wear
leave-----be away (from) buy-----have fall asleep----be asleep
end/finish-----be over catch a cold-----have a cold
join the army----be in the army be a soldier join the Party----be in the Party be a Party member
→My brother has been in the army for two years. →My brother has been a soldier for two years.
3.現在完成時中been to,gone to和been in/at been to去過某地,表示某人的一種經歷,可以和once,twice,already,ever,never等連用. eg. She has been to Shanghai twice. (表示目前人在這里)
gone to 去某地了,說話時某人已離開此地,在去某地的途中或已在某地,
eg. She has gone to Shanghai。 (表示現在她人不在這里)
been in/at 逗留在某地(已經一段時間).常和for ten days,since I came here等連用.
eg. She has been in Shanghai since she moved there.
4.現在完成時和一般過去時的區別
現在完成時所表明的是過去發生的動作對現在的影響,強調的是現在的情況,不可以和表示過去的時間狀語yesterday,in 1991,three days ago last time,last night等連用一般過去時表明的是過去發生的事實,和現在不發生關系.
5.現在完成時中的 for 與 since
for + 時間段 與延續性動詞的現在完成時連用 since + 時間點/從句
I have kept the library book for a week.= I have kept the library book since a week ago.
6. It is /has been +一段時間 + since 從句.自從某事發生已有一段時間了. eg. It is /has been two years since my brother joined the army. 注意:1.since 引導的從句中動詞用過去時
2.when 引導 的特殊問句不與現在完成時連用.
3.have got,has got 雖然是現在完成時,但have got=have has got==has
練習題: 1.It’s a long time since we ____ (meet) last,isn’t it?
2.--I know you _______ (choose) a picture book among these. --Yes,Have a look at it, please.
3.So far,spaceships without people _______ (reach) the moon and some other partsof the universe.
4.My father____ home for nearly three weeks.
A.has gone away from B.has left C.has been away from D.went away
5.Mr and Mrs Green have_____in China for a week. A.been B.got C.arrived D.reached
6.--Where’s Mary? --Oh,she _____the library.
A.has gone to B.went to C.has been to D.had gone to
H:過去完成時棗表示過去某一時間或動作之前已完成的動作
結構： 助動詞had + 動詞的過去分詞
用法： 1.表示在過去某一時間或動作之前已經發生或完成了的動作,動作發生的時間為“過去的過去“.表示過去某一時間可用by,before 等構成的短語,也可用when,before等引導的從句或通過上下文表示. eg. By the end of last term,we had learned a thousand English words.
He had finished his homework before his father came back last night.
2.表示過去某個時間之前發生的動作或狀態, 一直延續到這一過去時刻,或還將繼續下去. eg. When I got to know him, he had worked there for twenty years.(注意) 否定式 had not == hadn’t
時態的呼應
1.主句中謂語動詞如果是現在時或將來時,從句中的謂語動詞可以用任何所需要的時態, he wants to speak to the headmaster. He said that he won’t be free tomorrow. he came last night.
2.主句中的謂語動詞如果是過去時態,從句中的謂語動詞一般情況下要用過去時態的某種形式. He said that he was working hard on his Chinese.
he had a very good journey home. he hadn’t bought the present yet.
he would stop in Moscow on the way. 3.如果從句所述內容是客觀真理,則謂語動詞總是用一般現在時,而不受主句中謂語動詞時態的影響.
eg. Miss Gao told us that light travels much faster than sound.
4.時間或條件狀語從句中,若主句是一般將來時或祈使句,從句要用一般現在時代替將來時.
eg.Stop talking when the headteacher ______(walk)into the classroom.
Jim won’t watch TV until he ___ (finish) his homework every time.
練習題： 1.They were so pleased to see each other that they almost ____ (forget) everything else around. 2. The girl put on her dress and then _______ (go) to the mirror to look at herself.
思考題： 1.I____(leave)my ruler at home. Can I use yours?
2.Who’s Jack London? I ___ never ____ (hear) of that man before.
3.I’m afraid I ___ (keep) you waiting for such a long time.
4.--Where ___ you___ (be)? --I’m looking for you all the time.
5.____they____ (know) each other when they were young?
6.The baby will cry if she ___ (not see) her mother
