时间与原因状语从句.pptVIP

* Adverbial clauses of time / reason （时间、原因状语从句） Adverbial clause of time: when, while, as before, after since, till/until, by the time as soon as = the moment hardly…when = no sooner…than the first time, every/each time whenever等 when (特定时间或一段时间) ① 当…时侯 ----When I was a boy, I rode to school. ----When the lesson was over, we walked out of the lab. ② 就在那时 ----I was doing my homework when the light suddenly went off. ----He was about to sleep when someone knocked at the door. when / while / as的区别 过去进行时 过去将来时 while (一段时间) ① 当…时侯(从句的谓语必须是持续性动词, 用进行时或“be+表语”) ----While Mary was cooking, the children were playing outside. ----Strike while the iron is hot. ② 然而 (并列句, 侧重对比) ----You are sitting while I am standing. ③ 虽然(让步状语从句, 放句首) ----While I admit his good points, I can see his shortcomings. when / while / as的区别 趁热打铁。 as ① 当…时侯(侧重同时发生) ----As I was a child, I showed much interest in insects. 一边…一边… ----He often does homework as he listens to music. ③ 随着... ----As times goes on, I’m getting older and older. when / while / as的区别 ----It was midnight before he came back. 午夜他才回来。 ----Before I could say a word, she had run out of the room. 没等我开口, 她就跑出了房间。 before的用法 before有时译成“…(之后)才”, “还等…就” before的用法 ----It will be five years before I come back. 我五年之后才能回来。 ----It was not long before the enemy was driven out of their country. 不久之后敌人就被赶出了他们的国家。 It + be + 一段时间 + before… 句型 “在…之后才…” 注意:①主句用否定式，译成“不多久…就” ----It won’t be long before they understand each other. 不久他们就会相互了解。 ②时态—主将从现或前过后过 ----It is/has been 11 years since I came to Shanghai. ----It is/has been three years since I joined the Party. It is/has been + 一段时间 + since… 句型 “自从...以来已有...(时间)了” since的用法 注意:主句时态— 从句时态— 一般现在时/现在完成时 一般过去时 直到他生病他才意识到健康的重要性。(Not until…) ----Not until he was ill did he realize the importance of health. ----It was not until he was ill that he realized… 练一练 半倒 by the time 主句时态？ ----By the time he was fourteen, he __________ (teach) himself advanced mathematics. 想一想 过去