11.12 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(xù)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(xiàn)在完成時。
   I worked here for more than twenty years.
    (我現(xiàn)在已不在這里工作。)
   I have worked here for many years.   
    (現(xiàn)在我仍在這里工作。)


   小竅門: 當(dāng)現(xiàn)在完成時+一段時間,這一結(jié)構(gòu)中,我們用下面的公式轉(zhuǎn)化,很容易就能排除非延續(xù)動詞在完成時中的誤使。
   1) (對) Tom has studied Russian for three years.
    = Tom began to study Russian three years ago, and is still studying it now.
   2) (錯) Harry has got married for six years.
    = Harry began to get married six years ago, and is still getting married now.
   顯然,第二句不對,它應(yīng)改為 Harry got married six years ago. 或 Harry has been married for six years.













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