新目標八年級下冊Unit 6學案

不確定的時間狀語
3）現在完成時可表示持續到現在的動作或狀態，動詞一般是延續性的，如live, teach, learn, work, study, know.
過去時常用的非持續性動詞有come, go, leave, start, die, finish, become, get married等。
舉例：
　 i saw this film yesterday.（強調看的動作發生過了。）
　 i have seen this film. （強調對現在的影響，電影的內容已經知道了。）　
why did you get up so early?（強調起床的動作已發生過了。）
who hasn't handed in his paper?　（強調有卷子，可能為不公平競爭。）
she has returned from paris.　她已從巴黎回來了。
she returned yesterday. 她是昨天回來了。
he has been in the league for three years.(在團內的狀態可延續)
he has been a league member for three years.(是團員的狀態可持續)
he joined the league three years ago.　 ( 三年前入團，joined為短暫行為。)
i have finished my homework now.　
---will somebody go and get dr. white?
---he's already been sent for.　
注意：句子中如有過去時的時間副詞（如 yesterday, last, week, in 1960）時，不能使用現在完成時，要用過去時。
（錯）tom has written a letter to his parents last night.
（對）tom wrote a letter to his parents last night.
四、用于現在完成時的句型
1. it is the first / second time…that…結構中的從句部分，用現在完成時。
it is the first time that i have visited the city.
it was the third time that the boy had been late.
2.  this is the… that…結構，that 從句要用現在完成時.
this is the best film that i've (ever) seen. 這是我看過的最好的電影。
this is the first time (that) i've heard him sing.這是我第一次聽他唱歌。
典型例題
(1) ---do you know our town at all?
---no, this is the first time i ___ here.
a. was b. have been c. came d. am coming
答案b. this is the first time 后面所加從句應為現在完成時，故選b。
(2)     ---have you ____ been to our town before?
---no, it's the first time i ___ here.
a. even, come b. even, have come c. ever, come d. ever, have come
答案d. ever意為曾經或無論何時，反意詞為never，此兩詞常用于完成時。 this is the largest fish i have ever seen. it is / was the first time +that-clause 的句型中，從句要用完成時
五、 比較since 和for
since 用來說明動作起始時間，for用來說明動作延續時間長度。
i have lived here for more than twenty years.
i have lived here since i was born..
my aunt has worked in a clinic since 1949.　
some new oilfields have been opened up since 1976.
i have known xiao li since she was a little girl.
my brother has been in the youth league for two years.
i have not heard from my uncle for a long time.
注意：并非有for 作為時間狀語的句子都用現在完成時。
i worked here for more than twenty years. (我現在已不在這里工作。)