【正文】 ，不能說 I39。 She39。 句中的 fell (fall 的過去時(shí) )，是系動(dòng)詞，后跟形容詞，如： fall sick。描述一件事發(fā)生的背景時(shí)，用過去進(jìn)行；一個(gè)長動(dòng)作發(fā)生的時(shí)候，另一個(gè)短動(dòng)作發(fā)生。同時(shí)， when 表時(shí)間的同時(shí)性， 瑪麗在做衣服時(shí) 提供事情發(fā)生的背景，因此用過去進(jìn)行時(shí)。 2） 過去進(jìn)行時(shí)的主要用法是描述一件事發(fā)生的背景；一個(gè)長動(dòng)作發(fā)生的時(shí)候，另一個(gè)短動(dòng)作發(fā)生。t found. 答案 D. 前句是一個(gè)仍在持續(xù)的狀態(tài)，應(yīng)用進(jìn)行時(shí)，由于沒有找到，其影響仍然存在，應(yīng)用完成時(shí)，瞬間動(dòng)詞用于否定式時(shí)可用于完成時(shí)。t findC. has lost, haven39。 You are always changing your mind. 典型例題 My dictionary ___, I have looked for it everywhere but still___ it. A. has lost, don39。 The leaves are turning red. It39。 Mr. Green is writing another novel. (說話時(shí)并未在寫，只處于寫作的狀態(tài)。 They will have been married for 20 years by then. You will have reached Shanghai by this time tomorrow. 現(xiàn)在進(jìn)行時(shí) 現(xiàn)在進(jìn)行時(shí)的基本用法： a. 表示現(xiàn)在 ( 指說話人說話時(shí) ) 正在發(fā)生的事情。 Our teacher told us that Columbus discovered America in 1492. 將來完成時(shí) 1) 構(gòu)成 will / be going to do sth. 2) 概念 a. 狀態(tài)完成：表示某事繼續(xù)到將來某一時(shí)為止一直有的狀態(tài)。 When she saw the mouse， she screamed. My aunt gave me a hat and I lost it. 2 ) 兩個(gè)動(dòng)作相繼發(fā)生，可用一般過去時(shí)；如第一個(gè)動(dòng)作需要若干時(shí)間完成，用過去完成時(shí)。因此 前一句應(yīng)用過去進(jìn)行時(shí)。 He said that he had learned some English before. By the time he was twelve, Edison had began to make a living by himself. Tom was disappointed that most of the guests had left when he arrived at the party. 典型例題 The students ___ busily when Miss Brown went to get a book she ___ in the office. A. had written, left B， were writing, has left C. had written, had left D. were writing, had left 答案 D. 把書忘在辦公室 發(fā)生在 去取書 這一過去的動(dòng)作之前，因此 忘了書 這一動(dòng)作發(fā)生在過去的過去，用過去完成時(shí)。 When the police arrived, the thieves had run away. c. 表示意向的動(dòng)詞，如 hope, wish, expect, think, intend, mean, suppose 等，用過去完成時(shí)表示 原本 … ，未能 … We had hoped that you would e, but you didn39。 那時(shí)以前那時(shí)現(xiàn)在 2） 用法 told, said, knew, heard, thought 等動(dòng)詞后的賓語從句。t need to describe her. I ___ her several times. A. had met B. have met C. met D. meet 答案 B. 39。clock. 他一直睡到 10 點(diǎn)。clock. 他到 10 點(diǎn)才回來。 (表經(jīng)歷 ) 2)用于 till / until 從句的差異 延續(xù)動(dòng)詞用于肯定句，表示 做 …… 直到 …… 瞬間動(dòng)詞用于否定句，表示 到 …… ，才 …… He didn39。 (表結(jié)果 ) I39。 I have been here since 1989. 2) since +一段時(shí)間 + ago I have been here since five months ago. 3) since +從句 Great changes have taken place since you left. Considerable time has elapsed since we have been here. 4) It is +一段時(shí)間 + since 從句 It is two years since I became a postgraduate student. 延續(xù)動(dòng)詞與瞬間動(dòng)詞 1) 用于完成時(shí)的區(qū)別 延續(xù)動(dòng)詞表示經(jīng)驗(yàn)、經(jīng)歷； 瞬間動(dòng)詞表示行為的結(jié) 果，不能與表示段的時(shí)間狀語連用。 ) 小竅門：當(dāng)現(xiàn)在完成時(shí) +一段時(shí)間，這一結(jié)構(gòu)中，我們用下面的公式轉(zhuǎn)化，很容易就能排除非延續(xù)動(dòng)詞在完成時(shí)中的誤使。 I worked here for more than twenty years. (我現(xiàn)在已不在這里工作。t received his letter for almost a month. 比較 since 和 for Since 用來說明動(dòng)作起始時(shí)間， for 用來說明動(dòng)作延續(xù)時(shí)間長度。即動(dòng)作不發(fā)生的狀態(tài)是可以持續(xù)的。 This is the largest fish I have ever seen. It is / was the first time +thatclause 的句型中，從句要用完成時(shí)。 4 (2) Have you ____ been to our town before? No, it39。ve heard him 。ve (ever) seen. 這是我 看過的最好的電影。 （錯(cuò)） Tom has written a letter to his parents last night. （對(duì)） Tom wrote a letter to his parents last night. 用 于現(xiàn)在完成時(shí)的句型 1） It is the first / second time…. that… 結(jié)構(gòu)中的從句部分，用現(xiàn)在完成時(shí)。 ) I have finished my homework now. Will somebody go and get Dr. White? He39。 She returned yesterday. 她是昨天回來了。t handed in his paper?（強(qiáng)調(diào)有卷子，可能為不公平競爭。） Why did you get up so early? （強(qiáng)調(diào)起床的動(dòng)作已發(fā)生過了。 舉例： I saw this film yesterday. （強(qiáng)調(diào)看的動(dòng)作發(fā)生過了。 2）過去時(shí)常與具體的時(shí)間狀語連用，而現(xiàn)在完成時(shí)通常與模糊的時(shí)間狀語連用，或無時(shí)間狀語。其構(gòu)成： have (has) +過去分詞。m leaving tomorrow. Are you staying here till next week? 3 現(xiàn)在完成時(shí) 現(xiàn)在完成時(shí)用來表示之前已發(fā)生或完成的動(dòng)作或狀態(tài)，其結(jié)果的確和現(xiàn)在有聯(lián)系。常用詞為 e, go, start, arrive, leave, stay 等。ll write to you as soon as I arrive there. 4）在動(dòng)詞 hope, take care that, make sure that 等后。 The train leaves at six tomorrow morning. When does the bus star? It stars in ten minutes. 2）倒裝句，表示動(dòng)作正在進(jìn)行，如： Here es the bus. = The bus is ing. There goes the bell. = The bell is ringing. 3）在時(shí)間或條件句中。m going to play football tomorrow afternoon. (主觀安排 ) 一般現(xiàn)在時(shí)表將來 1）下列動(dòng)詞： e, go, arrive, leave, start, begin, return 的一般現(xiàn)在時(shí)表將來。 be going to 表示主觀的打算或計(jì)劃。 be going to/will 用于條件句時(shí)， be going to 表將來 will 表意愿 If you are going to make a journey, you39。 We are to discuss the report next Saturday. 4)be about to +不定式，意為馬上做某事。 The play is going to be produced next month。 a. 主語的意圖，即將做某事。 will 在陳述句中用于各人稱，在