since和for的区别如何使用.和时态的区别.要说的直白一点,
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since和for的区别如何使用.和时态的区别.要说的直白一点,
since和for的区别
如何使用.和时态的区别.要说的直白一点,
since和for的区别如何使用.和时态的区别.要说的直白一点,
Since 用来说明动作起始时间,for用来说明动作延续时间长度.例如：
I have lived here for more than twenty years.我住在这儿二十多年了.
I have lived here since I was born.我从出生起就住在这儿了.
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.）
注意：用句型转换的方法,很容易排除非延续动词在有for/since结构的完成时中的误用.
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.
都用于现在完成时，since+点时间，for+段时间，注意延续性动词与非延续性动词之间的转换，非延续性动词可以用于现在完成时，但不能与表示一段时间的状语连用。