【语法since和for用法讲解】
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。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.
同学们，看看since和for的用法比较，大家有没有清楚一点呀，多多看看哦。
国中英语分词与连词的'语法
【分词与连词的】在学习的时候需要注意的是，分词的主语和主句的主语必须为同一个哦！
有时为使分词短语与主句关系更清楚，可在分词前加连词。 连词有： when，while，if though，after, before, as. 但分词的主语和主句的主语必须为同一个，如：
While waiting there, he saw two pretty girls come out of the building.
waiting 和saw 的主语相同。
温馨提示：同学对这个如果还不是很理解的话，就不可以再偷懒了哦！
学识谷
