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新概念英语第二册 Lesson53
97
Hot snake
触电的蛇
First listen and then answer the question.
听录音，然后回答以下问题。
What caused the fire?
At last firemen have put out a big forest fire in California.
消防队员们终于扑灭了加利福尼亚的一场森林大火。
Since then, they have been trying to find out how the fire began.
从那时起，他们一直试图找出起火的原因。
Forest fires are often caused by broken glass or by cigarette ends which people carelessly throw away.
森林火灾时常由破碎的玻璃或人们随手扔掉的香烟头引起。
Yesterday the firemen examined the ground carefully, but were not able to find any broken glass.
昨天，消防队员仔细查看了地面，但未能发现碎玻璃。
They were also quite sure that a cigarette end did not start the fire.
他们还十分肯定火灾也不是由烟头引起的。
This morning, however, a firemen accidentally discovered the cause.
然而今天上午，一个消防队员偶然发现了起火的原因。
He noticed the remains of a snake which was wound round the electric wires of a 16,000-volt power line.
他发现了缠绕在16,000伏高压线上的一条死蛇。
In this way, he was able to solve the mystery.
就这样，他解开了起火之谜。
The explanation was simple but very unusual.
解释很简单，却异乎寻常。
A bird had snatched up the snake from the ground and then dropped it on to the wires.
一只鸟把蛇从地上抓起来，然后把它扔到了电线上。
The snake then wound itself round the wires.
于是蛇就缠住了几根电线。
When it did so, it sent sparks down to the ground and these immediately started a fire.
当它这样做时，把火花送到了地面，这些火花立刻引起了一场大火。
生字
vocabulary
1 hot [hɔt] a.带电的，充电的
2 fireman ['faiəmən] n.消防队员
3 cause [kɔ:z] v.引起 n.原因
4 examine [ig'zæmin] v.检查
5a ccidentally [ˌæksi'dentəli]ad.意外地,偶然地
6 remains [ri'meinz] n.尸体，残骸
7 wire['waiə] n.电线
8 volt[vəult] n.伏特(电压单位)
9 power line电力线
10 solve [sɔlv] v.解决
11 mystery ['mistəri] n.谜
12 snatch [snætʃ] v.抓住
13spark [spɑ:k] n.电火花
语法
grammar
本课主要对比复习一般过去时、现在完成时和现在完成进行时的用法：
（一) 构成方式
一般过去时的结构：主语 + was / were / 动词过去式
现在完成时的结构：主语+ have / has + 动词过去分词
现在完成进行时结构：主语+ have / has + been +动词现在分词
（二）常见用法
1、一般过去时侧重描写过去发生的动作或状态及具备的性格或能力等。例如：
I was tired yesterday.
我昨天很累。
Anna went to the cinema last week.
安娜上周去看电影了。
When I was a child, I was afraid of snakes.
当我小孩时我很害怕蛇。
2、现在完成时侧重描写过去发生的动作对现在造成的影响或结果。动作可能已经结束，也可能继续持续下去。例如：
They have lived here since ten years ago.
自从十年前他们就住在这里。
Have you stayed at his hotel?
你曾住过他家酒店吗？
Alice has never been to Paris.
爱丽丝从来没有去过巴黎。
3、现在完成进行时是我们在前一课，第52课刚学的新时态。主要侧重描写过去发生的动作持续到现在，而且还会继续持续下去。例如：
I have been reading the book since last night and I am still reading it now. (动作还会继续下去)
我从昨天晚上到现在一直仍然还在读这本书。
Have you been reading the book since last night?
你从昨晚一直在读这本书吗？
