before和until的用法及區(qū)別PPT學習教案

1、會計學1before和和until的用法及區(qū)別的用法及區(qū)別I waited _ he came back. 我一直等到他回來。 I didnt leave _ he came back .直到他回來我才走 I can only give you an answer _ I think it over. untiluntilbefore第1頁/共13頁until before 區(qū)別實際上，只要我們把握住兩者使用時本身的含義及主句動詞是終止性的，還是延續(xù)性的，肯定式，還是否定式兩大點，就能容易地解決這類問題。現(xiàn)詳細闡明如下： 一、在下列情況下，兩者可互換用，但含義略有不同。before表示“在之前

2、”的意思，強 調(diào)時間先后關系；而until表示“直到才”的意思，主句是肯定句則表示主句動作的終 止時間；主句是否定句則強調(diào)主句動作的起始時間。 第2頁/共13頁1.主句為否定式終止性謂語動詞。常見的動詞是open, start, leave, arrive, finish, stop等。 例如： (1)The noise of the street didnt stop until/before it was midnight. (2)The children wont come back until/before it is dark. (3)I didnt leave the lovely

3、 boy until/before his mother came home.第3頁/共13頁2.主句為肯定式、延續(xù)性謂語詞，這類動詞用stand, stay, talk, be, wait等。例如： (1)He lived with his parents until/before he graduated from school. (2)I will wait until/before he comes to my help. (3)I shall stay here until/before you come back. 第4頁/共13頁二、在下列情況下，用before不用until。

4、1.主句這肯定式、終止性謂語動詞，只用before。例： (1)He fell asleep before I could take off his clothes. (2)We arrived there before it started to rain. (3)The holiday came to the end before I knew it. (4)He almost knocked me down before he saw me.第5頁/共13頁2.主句謂語動詞強調(diào)動詞的遲緩性，只用before，常伴有時間段狀語或時間段暗示。例： (1)It was quite some t

5、ime before he found the elephant at all. (2)We had walked a long way before we found some water. (3)We had sailed for two days before we saw the land. (4)The fire lasted about four hours before the firefighters could control it. 第6頁/共13頁(5)It was midnight before my brother came home. (6)It was three

6、 months before they met again.3.如果強調(diào)從句謂語動作未發(fā)生，就發(fā)生主句謂語動作，只用before。常譯為“未及”，“不”或“不等就”。例：(1)We can leave early in the morning before it gets too hot. (2)I must write it down before I forget it. (3)We do want to buy something now before prices go up.第7頁/共13頁4.表“與其說倒不如”，“與其毋寧”只用before。例： (1)I would give u

7、p my job before Id agree to be dismissed. (2)He will die of hunger before he will steal. 5.在某些特定句型中用before。例如： (1)It was not long before the whole country rose up. (2)It will probably not be long before they understand each other.第8頁/共13頁 三、下列情況一般區(qū)別用until。 1.主句是持續(xù)性謂語動詞時，肯定、否定都可以，但意義完全不同。肯定表動作終止，而否定表

8、動作開始。例如： (1)We discussed the problem until/before he came back.我們一直討論到他回來。 (2)We didnt discuss the problem until he came back.我們一直等到他回來后才討論問題。第9頁/共13頁2.notuntil句型盡管在某些情況下可與before互換用，但在強調(diào)句中一般仍用until。 例如： (1)It was not until he told me that I knew it. (2)It was not until he finished his homework that he went home.第10頁/共13頁They were taking a peaceful wa