小学英语语法知识点：比较since和for

小学教育网

小学英语语法知识点：比较since和for
        　　Since 用来说明动作起始时间，for用来说明动作延续时间长度。
       
        　　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 作为时间状语的句子都用现在完成时。
       
        　　I worked here for more than twenty years.
       
        　　(我现在已不在这里工作。)
       
        　　I have worked here for many years.
       
        　　(现在我仍在这里工作。)
       
        　　小窍门：当现在完成时+一段时间，这一结构中，我们用下面的公式转化，很容易就能排除非延续动词在完成时中的误使。
       
        　　1)(对) Tom has studied Russian for three years.= Tom began to study Russian three years ago， and is still studying it now.
       
        　　2)(错) Harry has got married for six years.= Harry began to get married six years ago， and is still getting married now.显然，第二句不对，它应改为 Harry got married six years ago.　或 Harry has been married for six years.