教学目标
1. 围绕“禁止和警告”，学习应遵守交通规则的交通用语。排队看病，告诉人们应遵守公共秩序。家庭集会不要时间太久、太吵。
2. 学习情态动词must的用法。
3. 学习when, before, after等引导的时间状语从句，及if引导的条件状语从句。
重点难点
1. if引导的条件状语从句
(1)条件状语从句在复合句中作主句的条件状语。
(2)这种句子，如果主句是一般将来时，或者是含情态动词must, can, may的谓语动词时，从句则用一般现在时，如：
I won't go by plane if it rains tomorrow. 如果明天下雨我就不坐飞机去。
If you get up late, you'll be late for school. 如果起床晚了，你就要上学迟到。
You can pass the exam if you study hard. 假若你努力学习，你就能考试及格。
If you don't hurry, you will miss the train. 如果不快点，你 就赶不上火车了。
2. 时间状语从句
连词when, before, after引导的时间状语从句，要特别注意当主语是将来时时，从句要用一般现在时；主句的谓语动词是情态动词+动词，从句的谓语，用一般现在时；主句是祈使句时，从句也要用一般现在时。主句用过去时，从句也要用过去时态，从句可以放在主句之前，也可放在主句之后。如放在主句之前，从句用逗号与主句隔开。
When the lights are red, the traffic must stop.
He liked reading when he was young.
Please don't go to bed before your mother comes back.
3. You mustn't eat anything until you see the doctor.
直到你看了病才能吃东西。
until “直到…为止”，可作介词，也可作连词
(1)until 作介词时，后跟名词或相当于名词的词或短语。例如：My father worked until twelve at night. 我父亲一直工作到晚上十二点。
I didn't get up until ten in the morning last Sunday. 上星期日直到上午十点我才起床。
(2)作连词，引导一个时间状语从句，常用于“not…until”“直到…才”结构，此时，主句的动词是终止性的或称瞬间动词，比如：go, come, move, leave等。此时，翻译时要先译until 引导的句子和词组。如：
They won't go to bed until their mother comes back.
直到他们的妈妈回来了他们才去睡。
I didn't leave until he finished having breakfast.
直到他吃完了早饭我才走。
当主句是肯定形式，主句谓语动词是延续性的，翻译时英、汉语序相同。如：
I waited until he came. 我一直等到他来。
He'll sit here until 9 o'clock. 他将坐到九点钟。
(3)not…until 与 not…before的异同。
He didn't go to bed until he finished his homework. 这句话也可表达为：He didn't go to bed before he finished his homework.
但并不是任何情况下都可互换，在有具体的时间时，有区别。
如：He didn't go to bed until 11 o'clock. 他直到11点才去睡。
而He didn't go to bed before 11 o'clock. 表示他可能在十一点前，也可能在十一点以后睡觉。
4. 情态动词must的用法
must: 没有人称和数的变化，需和动词原形连用。
(1)表示必要，必须。
You must be careful!
We must study hard.
(2)表示推测，可能性很大，“一定”“必定”的意思。
She must be our new English teacher.
Mr. Wang must be at work. 王先生想必在工作。
(3)mustn't 表示“禁止”，绝对不许做(某事)。加强语气时用must never.
You must not play football on the road.
You must never talk to your father like that.
(4)回答 must 开头的问句时，肯定式用must, 否定式用needn't，不用 mustn't。
Must we do homework every day? Yes, you must. /No. you needn't.
知识总结
1. 掌握本单元单词积累部分词汇及词组。
2. 掌握must的用法。
3. 掌握when, before, after引导的时间状语从句及if引导的条件状语从句，特别是时态，主句和从句要一致。
核心知识
常用单词
alone, arrive, bell, care, change, complain, disturb, fact, half-way, head, hit, hurt, jumper, knee, live, mistake, necessary, noise, passenger, patient, plastic, police, push, quarrel, queue, quiet, quietly, surprise, telephone, themselves , turn, visitor, voice
at midnight 在半夜(子夜) enjoy oneself 过得快乐，玩得痛快 get off 下来，从…下来 get on 上(车)，have a good time 过得快乐， in fact 实际上，实事上 laugh at 嘲 笑， make a noise 吵闹，quarrel with sb 与某人吵架，stand in (the) line 站在队里 ， throw about 乱丢、抛散 waiting room 候诊室 catch a bus 赶车 be careful 当心， 小心 have an accident 出事故 wait in line 排队等候 wait for one's turn 等候轮到 某人，按次序等候 at a bus stop 在车站， a queue jumper 不排队等候的人，插队者 be in the queue 排队，站队 see a doctor 看病 take one's arm 拉某人的胳膊 get ready for 为…作准备 not…until… 直到…才… a plastic bag 塑料袋 complain about sb/s th 对某事不满，抱怨某事，抗议某事 in a tired voice 用疲倦的声音 at the head of 在…前面
基础知识
1. You must be more careful!你一定要更加小心!
careful 的比较级是 more careful
be careful “小心，当心”其同义词是look out, take care
Be careful not to play football in the street. 注意不要在街上踢球。
Take care when you cross the road. 过马路时要小心点。
Look out! The bus is coming!当心!车来了。
2. That car nearly hit you. 车几乎撞上你了。
nearly 副词、作状语，修饰动词 hit， 意思是“几乎，差不多”一般放在行为动词前，be 动词后，一般不修饰表否定意义的词。
如：I am nearly thirty. 我差不多三十岁了。
We are nearly ready for travel. 我们差不多为旅行作好了准备。
The old man nearly died. 那位老人几乎死了。
3. When you get on the bus, you mustn't push others.
当你上车时，你一定不要推别人。
get on“上(车)”，反义词 get off “下来，从…下来”
push“推” 反义词是 pull “拉、拖”
4. You must stand in the line and wait for your turn.
你应该排队按次序等候。
(1)stand in line “排队”近义词是wait in a queue 排队等候
注意下面说法：jump the queue 插队
wait in line=wait in a queue 排队等候
be in (the) line. 在队列里，排队=be in the queue
a queue jumper 插队的人。
(3)wait for one's turn 等着轮到某人，按顺序等候
如：Don't jump the queue. Wait for your turn, please.
不要插队，请按顺序等候
turn 这处是作名词，“顺序、次序”。句型：
It's one's turn to do sth. 轮到某人做某事
如：It's my turn to clean the blackboard. 轮到我擦黑板了。
It's Li Lei's turn to be on duty. 轮到李磊值日了。
5. It is better to wait and be safe. 最好等到安全。
It 在这句中是形式主语，to wait and be safe 是动词不定式作真正的主语。当不定式作 主语时，常常用it作形式主语，而将不定式放在句末，试比较：
To study English is not easy.
It is not easy to study English. 学习英语 不容易。
To climb that tree is dangerous.
It is dangerous to climb that tree. 爬那棵树危险。
It's bad for you to read in bed. 躺在床上看书对你有害。
To read in bed is bad for you.
6. The people are waiting for the doctor to come. 人们在等医生来。
“to come” 是动词不定式作宾语补足语，补充宾语“the doctor”。例如：
I invited Tom to have dinner with me this Sunday.
这个星期天我邀请汤姆同我吃晚餐。
I wanted him to wait for me after school.
我想要他放学后等等我。
We are waiting for the rain to stop. 我们正等着雨停下来。
The farmers waited for spring to come. 农民们期待着春天到来。
7. At the head of the queue was an old woman. 排在队伍前头的是一位老太太。
(1)at the head of 意为“在…前头”、“居首位”，反义词是at the end of “在…末尾 ”，如：
My father always sat at the head of the table. 我父亲总坐在桌子的上首。
I put my address at the head of the letter. 我把我的地址写在信的上方。
Li Ming is at the head of his class. 李明是班上第一名。
(2)本句是倒装句。在英语中，当表示地点、方位的介词短语放在句首时，句子常要倒装， 即将连系动词或谓语动词提到主语前面，(谓语常为不及物动词)：
On the left side of the river were rows of fruit trees. 河的左岸是一排排果树。
In front of the house stands a big tree. 房子的前面有一棵大树。
Behind the factory is a hospital. 工厂后面是一家医院。
Among the children sat an old man. 在孩子们中间坐着一个老人。
8. She wanted to see the doctor because her back hurt. 她要看病，因为她的背痛。
此处hurt是不及物动词，意为“痛”，如：
My feet hurt. 我的脚痛。
Does your leg still hurt? 你的腿还痛吗?
hurt 也可作及物动词用，表示“使…受伤”，如：
He hurt his back when he fell. 他摔倒时背部受了伤。
The boy hurt himself. 那孩子受伤了。
9. She sat nearest to the doctor's door. 她坐在离医生的门最近的地方。
(1)nearest 在这里是副词，near的最高级，副词最高级前可省去the, 如：
He studies hardest of all. 在所有的人中，他学习最努力。
They all came early but she came earliest. 他们都来得早，而她来得最早。
(2)near to, next to 都作“邻近”解，是far from的反义词，如：
He lives near to the post office. 他住在靠近邮局的地方。
I live nearer to the post office than you. 我住的地方比你住的更靠近邮局。
He lives next to me. 他住在我的隔壁。
The post office if next to the school. 邮电局就在学校隔壁。
She sat next to her mother. 她坐在她妈妈身旁。
10. She lives in the country. 她住在乡下。
in the country “在农村，在乡下”，对应词是in the city. “在城市”。
country 一词除指“国家”外，还有“农村、乡下”的意思，用时一般要加定冠词the(=the countryside)。例如：
be/come from the country 来自农村
live/work in the country 在农村生活(工作)
country 还可为形容词，作定语。例如：
a country girl 乡下姑娘； country life 乡村生活； country roads 乡间道路
I was born in the country but my younger sister was born in the city.
我出生在农村，但我的妹妹生在城里。
11. She stood up and took his arm. 她站起来，抓住他的手臂。
take sb's arm 意思是“抓住某人的手臂”。类似的用法有take sb's hand(s)，意思是“ 握住某人的手(双手)”。
12. Everyone laughed at the woman's mistake. 人人都为那妇女的错误而发笑。
laugh at 有“因……而发笑”或“嘲笑”的意思。再如：
Don't laugh at her. 不要嘲笑她。
They all laughed at my story. 他们听了我的故事都笑了。
Why do you laugh at this idea? 你为什么觉得这个想法好笑?
13. Why are you in bed? 你为什么还在床上?
in bed 有“睡觉”、“在床上”、“卧床”等意思，用时一般加“be”。再如：
Granny Li is still in bed. 李奶奶仍在卧床。
He is in bed with a cold. 他感冒躺下了。
14. I feel a little better now. 我现在感觉好一点。
a little 可用来修饰比较级，表示程度。
He is a little taller than I. 他比我高一点。
My desk is a little better than his.
我的课桌比他的好一点。
15. If you are ill, you'll have to see the doctor.
如果你病了，你得看病。
(1)be ill= be sick “生病”ill在系动词后，作表语。类似用法有：be quiet 安静，feel well 感觉舒服，be late 迟到， be alone 单独的，寂寞的。
(2)see a doctor “看病，看医生”
16. You mustn't throw them about. 你一定不要乱丢它们。
throw about “乱丢、抛散”。about 在此是副词，当宾语是名词时，可放在about前面和后面。宾语是代词时，只能放在throw about的中间。如：
Don't throw the waste paper about=Don't throw about the waste paper. 别把废纸到处丢。
These are your books. Don't throw them about. 别乱丢。
17. When my mother reached home. 当我妈妈到家时。
People in the USA can't drink beer or wine before they reach 21.
美国人在年龄到了21岁才能喝啤酒或白酒。
reach 及物动词，“到达”同义词是get和arrive，这两个词是不及物动词，后接地点名词时，要加介词，分别是get to 和arrive at(in). 大地点用in,
如：Last year they reached China=Last year they got to China=Last year they arrived in China.
18. Their friends enjoyed themselves at the party.
在晚会上他们的朋友玩的很愉快。
enjoy 后接反身代词，构成短语 enjoy oneself “过得快乐，玩的痛快，”=have a good time, enjoy 后有动词时，动词要加ing。
如：I enjoyed myself in the park last Sunday. 上周日我在公园玩的痛快。
He enjoyed himself on his birthday. 他生日过的快乐。
19. You must stop making so much noise. 你们必须停止吵闹。
(1)stop doing sth 停止做某事。
stop to do sth 停下来做某事。(指停下正做的事，来干另一件事)
如：He stopped to talk with me. 他停下来同我交谈。
When he saw our teacher coming, he stopped talking with me.
他看到老师来了，就停止同我谈话了。
(2)make a noise 吵闹 make much noise 太吵闹，发出大声，noise可作可数名词，也可作不可数名词。
典型例题
【课本难题解答】
1. If it rains tomorrow, we to visit the Museum.
A. don't go B. won't go C. aren't go D. didn't go
解析：在条件状语从句中，用一般现在时，而主句用一般将来时。故选B对。
2. After he heard the news, he me soon.
A. calls B. will call C. called D. is calling
解析：在含有时间状语从句的复合句中，主句和从句的时态要一致。从句用过去时，主句也 用过去时，故选C对。
3. An old grandpa is standing in the head of the queue. (找出错项并改正)
A B C D
解析：at the head of “在…前头”是固定搭配，故C错，in应改成at.
4. 直到我亲眼看到了，我才会相信这件事。
A. I won't believe it until I see it with my own eyes.
B. I believe it until I see it with my own eyes.
C. I didn't believe it until I see it with my own eyes.
解析：(1)not…until 是“直到…才…”的意思。(2)主句和until引导的时间状语的时态要保持一致。B句不是not…until. C句时态不一致，故选A对。
【关于“Unit 17 You must be more careful”的常见问题】
常见问题1: Unit 17 You must be more careful
问题：
读懂下文，并选择填空。
December 1 is Christmas Day. Christmas is an important(重要的) holiday 2 the United 3 . 4 this day, most families get together 5 a big dinner. They exchange(交换) presents and visit friends. The Christmas tree is an important 6 of the Christmas holiday. Most families buy a tree. The family decorate(装饰) the tree 7 .
Santa Claus(圣诞老人) has a white beard(胡子) and 8 a red suit(衣服 ). Parents always 9 their children that Santa Claus brings presents to all good children. He travels in a sleigh(雪橇) and comes down the chimney( 烟囱). He 10 the presents under the Christmas tree.
1. A. twenty five B. 25th C. 26th D. twenty and five
2. A. at B. on C. in D. to
3. A. State B. Nation C. States D. Country
4. A. In B. At C. Into D. On
5. A. for B. with C. in D. over
6. A. parts B. part C. party D. the part
7. A. alone B. everyone C. together D. both
8. A. put on B. wears C. put in D. wear
9. A. tell B. told C. tells D. say
10. A. puts B. put C. putting D. to put
解答:
分析：1. B。12月25日是圣诞节 2. C。在某国用介词in 3. C。用复数 4. D。在具体某一天用介词on 5. A。for表示目的或原因 6. B 7. C 8. B。wear表示穿的状态。用一般现在时与上句谓语一致 9. A 10. A。用puts与整篇时态一致。
常见问题2: Unit 17 You must be more careful
问题：
不变原意改写句子。(山西 2000)
1. Uncle Wang is on a visit to Japan.
Uncle Wang Japan.
2. We were all here before you.
We all here you.
3. You must be careful. That car nearly hit you.
You must . That car nearly hit you.
4. You must always wait in a line.
You must always wait .
5. It's very nice talking to you.
It's very you.
6. Why don't you come and play basketball?
and playing basketball?
7. It's so hot that I can't wear the coat.
It's to the coat.
8. You mustn't eat anything until you see the doctor.
anything you see the doctor.
解答:
1. is visiting 2. came, earlier, than 3. take care 4. for your turn 5. nice to talk to 6. What about coming 7. too hot, wear 8. Don't eat, until
常见问题3: Unit 17 You must be more careful
问题：
单元写作书面表达：根据图画提示完成下列对话。
①Bill 说，瞧多高的一棵树啊!Jack说他要爬那棵树，他擅长爬树。Bill说，小心，很危险的。Jack说不危险他可从树上把花摘下来。Bill 劝告他，千万别干，树太高了，Jack不听，他说很容易的。结果从树上摔了下来。
②用上这些提示词：climb up, be good at, be careful， look out，dangerous， pick ， flowers， easy.
Bill: Look, What a tall tree.
Jack: 1 . 2 . Let me show you.
Bill: 3 , Jack. It's dangerous.
Jack: No, 4 . It's quite safe. 5 .
Bill: You mustn't do it, Jack. 6 .
Jack: It's 7 . I can do it. Watch!
Bill: 8 !
Jack: Ouch!(He falls off the tree)
解答:
1. I'll climb up the tree. 2. I'm good at climbing trees. 3. Be careful. 4. It's not dangerous. 5. I can pick some flowers from the tree. 6. It's too high . 7. easy 8. Look out.