课文详注 Further notes on the text
1．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。
（1）at last（终于，到底）表示经过一番努力之后。
（2）put out可以表示“扑灭”、“熄灭”、“关掉”等含义：
Please put the light/ fire out.
请把灯关掉／把火灭掉。
（3）forest虽然是名词，但在句中起形容词的作用，修饰fire。
2．…they have been trying to find out how the fire began.
……他们一直试图找出起火的原因。
（1）短语动词find out表示经过研究、努力等“发现”、“找出”、“查出”：
I'll try and find out the name of the person who saved my life yesterday.
我将设法查出昨天救我命的那个人的姓名。
（2）how the fire began是find out的宾语，它是一个由疑问词how引导的名词从句。
3．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。
（1）start作及物动词时可以表示“使……发生”、“引起”。
（2）be sure后面跟的是名词从句。that引导的这个名词从句也可以写成that the fire was not started by a cigarette end。但这里强调的是引起火灾的原因（不是碎玻璃或烟头），所以用烟头作主语。
4．…a fireman accidentally discovered the cause.
……一个消防队员偶然发现了起火的原因。
discover本身含有偶然发现（某个已经存在的东西）的含义：
I don't know who discovered America.
我不知道谁发现美洲的。
在discover前面加上accidentally更加强了“偶然”、“意外”的含义。
5．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。
（1）the remains表示“尸体”、“残骸”，必须用复数形式：
The villagers were surprised to see the remains of an aeroplane near the lake.
村民们惊讶地发现湖边有一架飞机的残骸。
（2）wound为wind的过去分词。wind在这里不表示“蜿蜒”，而表示“卷在……上”、“缠绕”，常与around／round连用：
Did you wind this piece of wire round the tree?
是你把这根铁丝缠在树上的吗？
（3）wire指具体的电线、铁丝等，line在这里指“线路”，含义比wire广。
6 ．When it did so…
当它这样做时……
so常用于一些动词之后，代指前面提过的某个动作／某件事，以免重复。
语法 Grammar in use
一般过去时、现在完成时与现在完成进行时（cf．第29课与第52课语法）
一般过去时通常与一个表示确切的时间的状语连用，现在完成时则有时与表示一段时间的状语连用，有时不需要时间状语，而现在完成进行时则有时与表示一段时间的状语连用，有时与all 表示时间的名词连用。现在完成时与一般过去时中既可以用状态动词（表示存在、拥有、感情、思想、需求等的动词）也可以用行为动词，现在完成进行时则通常与行为动词连用。
词汇学习 Word study
1．throw
throw作及物动词主要含义为“投”、“掷”、“抛”、“扔”。当它与不同的介词或副词连用时，其意义会稍有变化。throw away表示“扔掉”、“丢弃”；throw at表示对准某一目标扔；throw to则表示扔给（某人）：
Many people throw away cigarette ends carelessly.
许多人随手乱扔香烟头。
Shall I throw this old newspaper away?
我把这旧报纸扔掉好吗？
Don't throw stones at the dog/ the window.
别对着狗／窗子扔石头。
I threw the ball to John but Tom caught it.
我把球扔给约翰，但汤姆接住了球。
2．cause与reason
（1）cause作名词时最重要的含义是“原因”、“起因”：
A fireman accidentally discovered the cause of the fire.
一个消防队员偶然发现了起火的原因。
Do you know the cause of the war?
你知道这场战争的起因吗？（cause通常与of连用）
cause作动词时可以表示“使……产生／发生”、“引起”：
Forest fires are often caused by broken glass or cigarette ends.
森林火灾时常由碎玻璃或香烟头引起。
What caused the accident?
事故是如何造成的？
（2）reason作名词时最重要的含义是“理由”、“原因”：
Give me your reasons for going there.
请告诉我你去那里的理由。
What was the reason for the delay?
延迟的原因是什么？
作“原因”讲时，reason与cause可以互相交换使用，但reason与介词for连用，而cause则与介词of连用：
What was the cause of the delay?
延迟的原因是什么？
reason后面通常跟why引导的从句：
That was the reason why the meeting was put off.
这就是会议推迟的原因。
reason作动词时表示“推理”、“劝导”、“说服”等：
How can you reason with him when he is so worried?
他现在如此担心，你怎么能劝得了他？
3．drop与fall
drop既可作及物动词又可作不及物动词，表示“（使）掉下”、“（使）落下”、“放下”：
As he walked past the tree, an apple dropped from it.
当他走过那棵树时，一个苹果从树上掉了下来。
The waiter dropped a fork.
那侍者掉了一把叉子。
He dropped the bag on the floor.
他把包放在地板上。
fall通常为不及物动词，表示“落下”、“（雨、雪）下”、“降”、“跌倒”、“摔倒”：
I fell and hurt myself.
我摔倒了并受了伤。
Please hold the vase and don't let it fall.
请拿住这花瓶，别让它倒了。
When leaves fall in autumn, I'll come back.
秋天叶落时，我就会回来。
练习答案 Key to written exercises
1．关键句型练习答案
C
Jack looked at his watch for the twentieth time. Suddenly Jill arrived. ‘I've been waiting for over an hour,’ he said angrily. ‘You never come on time. ’ ‘Oh, is that so?’ Jill answered. ‘Were you here at 2.30?’ Jack went red. ‘Well,’ he said, ‘I go here five minutes late myself, but you weren't here. ’ ‘I came here at exactly 2.30,’ Jill said, ‘and I waited for five minutes, but you didn't come. ’ ‘What have you been doing since then?’ Jack asked. ‘I've just been to the hairdresser's,’ Jill answered brightly.
2．难点练习答案
a
Look, you threw the potato-peeler away by mistake.
The shepherd threw some food to his dogs.
The teacher threw some chalk at a boy who wasn't listening.
b
I'm quite certain these are my glasses.
The children are very quiet. What's going on?
c
The cause of unemployment is complicated.
Can you explain the reason for changing our arrangements?
He reasoned that we would have to comply, even if we didn't wish to.
d
Please don't drop that vase!
It fell from my hands and broke.
3．多项选择题答案
1c 2d 3a 4c 5c 6c
7d 8c 9d 10a 11c 12c
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