Since-和-for-的用法及区别

Since 和 for 的用法与区别：一，since 的四种用法1，since + 过去一个时间点〔如具体的年、月、日期、钟点、ago. 1990 , last month , half past six I have been here since 1990. 1990 起，我一直在这儿。2，since+ 一段时间+ago I h a v e b e e n h e r e s i n c e f i v e m o n t h s a g o 。自从五个月前，我已经在这儿了。3，since+从句 Great Changeshave taken place since you left. 自从你走后，已经发生了很大的变化。4，It is +一段时间+since 从句I t i s t w o y e a r s s i n c e I b e c a m e a n E n g l i s h t e a c h e r . 我成为英语老师有两年了。2，For + 时间段，用来说明动作延续时间长度，因此句中的谓语动词，也应该是延续性动词。I have been in Beijing for one year。We have learnt English for about three years. I have been here for 3 days. (对) I have arrived here for 3 days.〔误〕三，延续性动词和终止 性动词的概念英语中，动词按其动作发生的方式、动作发生过程的长短，可分为延续性动词和终止性动词。延续性动词表示能够延续的动作，这种动作可以延续下去或产生持久影响。如：learn, work, stand, lie, know, walk, keep, have, wait, watch, sing, read, sleep, live, stay 等。终止性动词也称非延续性动词、瞬间动词或短暂性动词，表示不能延续的动作，这种动作发生后立即完毕。如open, close, finish, begin, come, go, arrive, reach, get to, leave, move, borrow,buy等。四、延续性动词的用法特征1.延续性动词可以用于现在完成时，其完成时态可与表示"段时间"的状语连用。表示"段时间"的短语有：for two years, during the past three years, since last year, how long 等I have learned English since I came here.自从我来到这儿就学英语了。 2.延续性动词不能与表示短临时间的"点时间"状语连用。如：It raind at eight yesterdaymorning. 〔误〕 rain 为延续 性 动词，而 at eight 表示"点时间"，前后显然矛盾。假如用延续性动词性动词来表示一瞬间的动作，可借助 come begin get 等终止性动词来表示。上句可改为：It began to rain at eight yesterday ...