(共38张PPT)
Unit 13 We’re trying to save the earth!
九年级
人教版
全
语法讲练及解析
（一）时态复习（Ⅰ）——现在进行时和现在完成时
一、现在进行时
We are studying in the classroom now. 现在我们正在教室里学习。（目前正在发生）
Are you preparing for the final exam these days 这段时间你在为期末考试做准备吗？（现阶段正在发生）
【拓展延伸】
（1）come、go、leave、start、arrive 等动词可以用现在进行时表示将要发生的动作。
John is coming here next week and will stay here until May. 约翰下星期要来这里，将在此待到五月。
（2）现在进行时可表示反复发生的动作，常与 always、all the time 等连用，多伴有一定的感彩，如不满、赞赏等。
Eg.He is always thinking of others. 他总是为别人着想。
（3）以下动词通常不用于现在进行时：
①表示感觉或感情的动词，如 smell、taste、seem、like、love、wish、hope 等；
②表示理解、记忆或决定等的动词，如 remember、understand、believe、decide 等；
③表示所有或占有的动词，如 have、belong、own 等。
【即学即用】
1.Look! The police _______ the food onto the bank of the river.
A.am carrying B. is carrying C. are carrying D. are carried
2.—Wow! Look out of the window! It______.
—Yes, what heavy snow! You know it______quite often here in winter.
A. is snowing; snows B. snows; is snowing
C. snows; snows D.is snowing; is snowing
3.Please don't make so much noise. The baby_______now.
A. Sleeps B. slept C. will sleep D. is sleeping
B
A
D
二、现在完成时
I have already had supper. 我已经吃过晚饭了。（表示现在不饿了）
I have been in the army for 5 years. 我在部队已经待 5 年了。
They have lived here since 20 years ago. 他们从 20 年前就住在这里了。
【拓展延伸】
在现在完成时的肯定句中，非延续性动词（短语）（如 come、go、arrive、leave、join、become、die、buy等）不能与表示一段时间的时间状语连用。若与表示一段时间的时间状语连用，非延续性动词（短语）要转成相应的延续性动词或短语。常见的有：
【即学即用】
1.He promised to pick me up at the school gate. However, he_____yet.
A. didn’t arrive B. doesn’t arrive C. isn’t arriving D. hasn’t arrived
2.—Mr. Li will check our homework this afternoon. ____you______it
—Not yet. I'm doing it right now.
A. Do; finish B. Had; finished C. Will; finish D. Have; finished
3.My grandparents______in that city since 2008.
A. will live B. live C. have lived D. were living
D
D
C
4.—What do you usually do in your spare time
—I often go to our community library. It ____ for two years in order to encourage us to read more.
A.opens B.has opened C.has been opened D.has been open
D
（二）被动语态
一、语法概述
被动语态表示主语是动作的承受者。其基本结构是 。
二、被动语态的构成
【拓展延伸】含情态动词的被动语态的结构是“情态动词+be+及物动词的过去分词”。
Lights must be turned off when we leave the classroom. 我们离开教室的时候必须关灯。
三、主动语态和被动语态的转换
将主动句变为被动句时，有如下步骤：
1.确定主动句的主语、谓语和宾语；
2.把主动句里的宾语变为被动句里的主语，若主动句里的宾语是人称代词，要将宾格变为主格；
3.把谓语变成被动结构“be+动词的过去分词”，但时态不改变;
4.把主动语态中的主语放在介词by 后作宾语，若主语是人称代词，应把主格变为宾格。
【特别提醒】在含有使役动词（如：make）或感官动词（see、watch、notice、hear 等）的主动语态的句子中，这些词后常跟省略 to 的动词不定式，但是改为被动语态时则要把省去的 to 还原。
Eg.I saw him cross the road and enter the shop. → He was seen to cross the road and enter the shop.
我看到他穿过马路进了商店。
四、适合用被动语态的情况
1.当动作的执行者不必或不易说出时，用被动语态。
Eg.The flowers are watered every morning. 这些花每天早上（被人）浇水。
2.需要突出或强调动作的承受者时，用被动语态。
动作的执行者由 by 引出且置于谓语动词之后，也可省略“by+动作的执行者”。
Eg.The new teacher is liked by all the students. 这名新老师被所有学生喜爱。
3.表示“据说/据报道/人们相信等”，常用“It is+过去分词（said/reported/believed 等）+that 从句”句型。
Eg.It is reported that a rainstorm is coming. 据报道，一场暴风雨就要来了。
五、不能用被动语态的情况
1.系动词 get、turn、seem、look、sound 等后接形容词作表语时，不能用被动语态。
2.There be 句型不使用被动语态。
3.主动句中宾语是反身代词的没有被动语态。
4.不及物动词或词组没有被动结构，如 take place（发生）、happen（发生）、come about（发生）、break out
（爆发）、appear（出现）、disappear（消失）、last（持续）等。
5.write、wash、sell 和副词 well、easily 等连用，且主语是物时，通常用主动形式表示被动含义。
Eg.This kind of bike sells well. 这种自行车卖得很好。
【即学即用】
1.—At present, one of the best ways to study is working in groups.
—More chances to students to learn from each other.
A. offer B. are offered C. have offered D. are offering
2.—Your city looks beautiful!
—Yes.Lots of trees and grass last year.
A.are planted B.have planted C.were planting D.were planted
3.My mother told me that my homework must on time.
A.finish B. be finish C. be finished D. finished
B
D
C
（三）情态动词
一、语法概述
情态动词表示说话人对所述动作或状态的态度或看法。情态动词一般没有人称和数的变化，在句中不能单独作谓语，必须和动词原形连用。初中阶段常用的情态动词有 can/could、may/might、must/have to、 should/ought to、would、need 等。
（三）情态动词
一、语法概述
情态动词表示说话人对所述动作或状态的态度或看法。情态动词一般没有人称和数的变化，在句中不能单独作谓语，必须和动词原形连用。初中阶段常用的情态动词有 can/could、may/might、must/have to、 should/ought to、would、need 等。
二、情态动词的基本用法
情态动词 用法 例句
can/could 表示能力，意为＂能，会＂ I can read this sentence in English. 我能用英语读这
句话。
表示许可时，意为＂可以，能够＂， 相当于 may She said that I could use her computer. 她说我可以使
用她的电脑。
用于推测，表示可能性，意为＂可能＂，could 比 can 更加不肯定，多用于否定或疑问句 The man can’t be our teacher — he has gone to Beijing. 那个男人不可能是我们的老师，他去北京了。
There is someone outside — who can it be 有人在外
面，可能是谁呢？
【知识拓展】 can 的一般疑问句，肯定回答用 Yes, ...can；否定回答用 No, ...can’t。 —Can you play the piano 你会弹钢琴吗 —Yes, I can. 是的，我会。/No, I can’t 不，我不会。 2. can，could 和 be able to 的区别：can 只有现在式和过去式，而 be able to 可以用于各种 时态；can( could)表示能力时，可用 be able to 代替。 I can(am able to) afford the car. 我能买得起这辆小汽车。 She has been able to come to school. 她已经能去学校了 I could(=was able to) drive a car before I left school. 毕业前我就会开车。 may/might 表示允许或许可，意为＂可以＂ May I use your phone 我可以用用你的电话吗？
表示征询许可时，might 比 may 的语气委婉 —Might I ask for a photograph of your little daughter 我能要一张你小女儿的照片吗
—Yes, you may. 是的，你可以。
用于表推测时，是＂可能，或许＂之意，might 语气更加不肯定，多用于 肯定句 He may be wrong, but I’m not sure. 也许他错了，但我也不确定。
She might be very busy now. 她现在可能非常忙。
【知识拓展】 may 的一般疑问句，肯定回答用 Yes, ...may. /Yes, of course. /Yes, certainly.；否定回答用 No, ...can’t/mustn’t。 —Might/May I smoke in this room 我可以在这间屋子里抽烟吗 —Yes, you may. 是的，你可以。/No, you can’t/mustn’t. 不，不可以。 用于表示推测时，may 和 might 一般不用于疑问句，而在疑问句中，常使用 can；在否定句中，may not/might not 意为＂可能不＂，而 can’t/couldn’t 意为＂不可能＂。 The young people might not like the idea. 年轻人可能不喜欢这个主意。 It can’t/couldn’t be our headmaster. He has gone to America. 那人不可能是我们校长。他已经去美国了。 must 表示必须，一定要，指说话人的主观语气 You must obey the school rules. 你必须遵守校
规。
mustn’t 表示禁止，意为＂千万不要，禁止＂，是说话人强有力的劝告 You mustn’t play with the knife or you may hurt
yourself. 你禁止玩刀否则你可能会伤到自己。
表示推测时，用于肯定句，意为＂想必，一定＂，否定句中用 can’t/couldn’t 来代替 This must be your room. 这一定是你的房间。
He must be eighty now. 他现在想必有八十岁了。
【知识拓展】 must 的一般疑问句，肯定回答为 Yes, ...must.；否定回答为 No, ...needn’t./No, ...don’t have to. —Must I clean the classroom now 我必须现在打扫教室吗？ —Yes, you must. 是的，你必须。/No, you don’t have to. /No, you needn’t. 不，你不必。 2. must 和 have to 的区别： ①用 must 表示＂必须＂的意思时，通常着重于说话者的主观看法，认为有必要去做某事；而 have to 着重于客观需要，含有＂不得不＂的意思。 We must study English hard. 我们必须努力学习英语。 You are ill today. You have to see a doctor. 你今天病了，不得不去看医生。 ②用 must 表示＂必须＂，只有现在时态的形式，如果要表示过去时或将来时的＂必须＂，就要用 have to 的相应形式。 You must drive fast to catch the time. 你必须开车开快点来赶时间。 They will have to leave tomorrow morning. 他们必须明天早晨起程。 would 作为 will 的过去式，可表示过去的意志、愿望或决心等，意为＂愿意＂ He promised he would never smoke again. 他承诺他再也不吸烟了。
表示过去反复发生的动作或某种倾向 Their English teacher would tell them stories in English after class. 他们的英语老师总是在课
后用英语给他们讲故事。
用于第二人称疑问句中，表示现在的请求、建议，比 will 的语气委婉 Would you please pass the English-Chinese dictionary on to Mary 请把这本英汉词典传
给玛丽好吗
【知识拓展】 would like 意为＂愿意，想要＂； would like/love to do sth 意为＂愿意/想要做某事＂； would like sb to do sth 意为＂想要某人做某事＂。 Would you like a cup of tea 你想喝杯茶吗？ Would you like to sing a song 你想唱首歌吗？ I would like you to wake me up at 5:30 tomorrow morning. 我想让你在明天早晨 5:30 叫 醒我。 should shall 的过去式，用于第一、三人称，多用于间接引语中，以征求对方意见 I asked the manager if I should have a few days off. 我问经理我是否可以请几天假。
表示义务，职责时，意为＂应当，应该＂，往往表示说话者的观点
表示惊讶、遗憾等，意为＂竟然，居然＂
need 表示＂需要，必须＂，多用于疑问句和否定句 Need you go so soon 你需要这么早走吗
You needn’t come so early. 你不必来这么早。
【知识拓展】 need 的一般疑问句，肯定回答为 Yes, ... must.；否定回答为 No, ... needn’t. —Need he finish the article next week 他需要下星期完成这篇文章吗 —Yes, he must. 是的，他必须完成。/No , he needn’t. 不，他不需要。 have to 表示不得不，说明客观条件只能如此；有时态形式的变化；否定式 don’t have to 意为＂不必＂(= needn’t) My brother was very ill, so I had to call the doctor in the midnight. 我弟弟病得厉害，我只得半夜里把医生请来。
I haven’t got any money with me, so I’ll have to borrow some from my friend.
我身上没带钱，只好向朋友借点了。
语法小测
一、单项选择
1.—Mary,where is Paul
—He ____a speech on Western art to the first-year students in the hall.
A.gives B.gave C.is giving D.has given
2.Paul is a foreign teacher in our school.So far, he____ for over four years.
A.was teaching B.has taught C.will teach D.taught
3.So far this year, the government_____ many new houses in Wenchuan.
A.build B.are built C.will build D.has built
C
B
D
4.—Can sixteen-year-olds drive their cars to school
—No.They shouldn’t_____ to drive because they are not serious enough.
A.allow B.allowed C.be allowed D.have allowed
5.My sister____ Qingdao two years ago, she for two years.
A. has left; has left B. left; has been away
C. left; has left D.has left; left
6.I_____ the History Museum twice. I've learned a lot there.
A. visit B. am visiting C. have visited D. will visit
C
B
C
7.—____ I return the book today, Mr. Lin
—No, you ___. You can keep it for two days.
A. May; mustn’t B. Must; mustn’t C. Must; needn’t D. Can; shouldn’t
8.The dictionary at the Lost and Found office ___be Tim’s, because his name is on its corner.
A. can B. can’t C. must D. mustn’t
9.This kind of pen ___and is also very cheap. I think you can buy some.
A.writes well B.writes good C.is written well D.is written good
C
C
A
10.—Do you know the famous artist in red
—Sure. He____ to the art festival in our city every year.
A.invites B.invited C.is invited D.was invited
11.—Look! The man at the gate___be our headmaster. He is always standing there every morning.
—No, it____be him. He is holding a meeting in the office now.
A. must; can’t B. must; mustn’t C. can’t; can’t D. can’t; mustn’t
12.Paper____ first____about 2000 years ago in China.
A. is; creating B. is; created C. has; created D. was; created
C
A
D
13.There's only one day to go. You ___finish your schoolwork by tomorrow.
A. can B. may C. will D. must
14.I won’t go to her party unless my best friend Jack_____.
A. will invite B. will be invited
C. is invited D. invites
15.---Is that man Mr. Smith
--- It_____be him. He has gone to New York on business.
A. can’t B. may not C. mustn’t D. needn’t
D
C
A
二、动词应用（根据短文内容,用括号内所给动词的适当形式填空,必要时可加助动词或情态动词。）
Scientists are trying 1.________ (make) deserts into good land again. They want 2.________(bring) water to the deserts, so people can grow crops and 3. _______(live) there. They 4. ___________(learn) a lot about the deserts. But more and more of the earth is 5. _________(become) deserts all the time.
Why is this true Scientists think that people are making deserts. People are doing bad things to the earth.
to make
to bring
live
are learning
becoming
Some places on the earth 6.___________(not have) much rain, but they don’t become deserts. This is because some green plants are growing there. Small green plants and grass 7._________(be) very important to dry places. Plants prevent the sun from 8._________(make) the earth drier. Plants prevent the wind from blowing the earth away. When a little bit of rain 9. ________(fall), the plants hold the water. Without plants, the lands 10._________(become) deserts easily.
don’t have
are
making
falls
become
Thanks!
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Unit 13 We’re trying to save the earth!语法讲练
（一）时态复习（Ⅰ）——现在进行时和现在完成时
一、现在进行时
We are studying in the classroom now. 现在我们正在教室里学习。（目前正在发生）
Are you preparing for the final exam these days 这段时间你在为期末考试做准备吗？（现阶段正在发生）
【拓展延伸】
come、go、leave、start、arrive 等动词可以用现在进行时表示将要发生的动作。
John is coming here next week and will stay here until May. 约翰下星期要来这里，将在此待到五月。
现在进行时可表示反复发生的动作，常与 always、all the time 等连用，多伴有一定的感彩，如不满、赞赏等。
Eg.He is always thinking of others. 他总是为别人着想。
以下动词通常不用于现在进行时：
①表示感觉或感情的动词，如 smell、taste、seem、like、love、wish、hope 等；
②表示理解、记忆或决定等的动词，如 remember、understand、believe、decide 等；
③表示所有或占有的动词，如 have、belong、own 等。
【即学即用】
Look! The police the food onto the bank of the river.
A.am carrying B. is carrying C. are carrying D. are carried
—Wow! Look out of the window! It .
—Yes, what heavy snow! You know it quite often here in winter.
A. is snowing; snows B. snows; is snowing
C. snows; snows D.is snowing; is snowing
Please don't make so much noise. The baby now.
A. Sleeps B. slept C. will sleep D. is sleeping
二、现在完成时
I have already had supper. 我已经吃过晚饭了。（表示现在不饿了）
I have been in the army for 5 years. 我在部队已经待 5 年了。
They have lived here since 20 years ago. 他们从 20 年前就住在这里了。
【拓展延伸】
在现在完成时的肯定句中，非延续性动词（短语）（如 come、go、arrive、leave、join、become、die、buy等）不能与表示一段时间的时间状语连用。若与表示一段时间的时间状语连用，非延续性动词（短语）要转成相应的延续性动词或短语。常见的有：
【即学即用】
He promised to pick me up at the school gate. However, he yet.
A. didn’t arrive B. doesn’t arrive C. isn’t arriving D. hasn’t arrived
—Mr. Li will check our homework this afternoon. you it
—Not yet. I'm doing it right now.
A. Do; finish B. Had; finished C. Will; finish D. Have; finished
My grandparents in that city since 2008.
A. will live B. live C. have lived D. were living
—What do you usually do in your spare time
—I often go to our community library. It for two years in order to encourage us to read more.
A.opens B.has opened C.has been opened D.has been open
（二）被动语态
一、语法概述
被动语态表示主语是动作的承受者。其基本结构是 。
二、被动语态的构成
【拓展延伸】含情态动词的被动语态的结构是“情态动词+be+及物动词的过去分词”。
Lights must be turned off when we leave the classroom. 我们离开教室的时候必须关灯。
三、主动语态和被动语态的转换
将主动句变为被动句时，有如下步骤：
1.确定主动句的主语、谓语和宾语；
2.把主动句里的宾语变为被动句里的主语，若主动句里的宾语是人称代词，要将宾格变为主格；
3.把谓语变成被动结构“be+动词的过去分词”，但时态不改变;
4.把主动语态中的主语放在介词 by 后作宾语，若主语是人称代词，应把主格变为宾格。
【特别提醒】在含有使役动词（如：make）或感官动词（see、watch、notice、hear 等）的主动语态的句子中，这些词后常跟省略 to 的动词不定式，但是改为被动语态时则要把省去的 to 还原。
Eg.I saw him cross the road and enter the shop. → He was seen to cross the road and enter the shop.
我看到他穿过马路进了商店。
四、适合用被动语态的情况
当动作的执行者不必或不易说出时，用被动语态。
Eg.The flowers are watered every morning. 这些花每天早上（被人）浇水。
需要突出或强调动作的承受者时，用被动语态。
动作的执行者由 by 引出且置于谓语动词之后，也可省略“by+动作的执行者”。
Eg.The new teacher is liked by all the students. 这名新老师被所有学生喜爱。
表示“据说/据报道/人们相信等”，常用“It is+过去分词（said/reported/believed 等）+that 从句”句型。
Eg.It is reported that a rainstorm is coming. 据报道，一场暴风雨就要来了。
五、不能用被动语态的情况
系动词 get、turn、seem、look、sound 等后接形容词作表语时，不能用被动语态。
There be 句型不使用被动语态。
主动句中宾语是反身代词的没有被动语态。
不及物动词或词组没有被动结构，如 take place（发生）、happen（发生）、come about（发生）、break out
（爆发）、appear（出现）、disappear（消失）、last（持续）等。
write、wash、sell 和副词 well、easily 等连用，且主语是物时，通常用主动形式表示被动含义。
Eg.This kind of bike sells well. 这种自行车卖得很好。
【即学即用】
—At present, one of the best ways to study is working in groups.
—More chances to students to learn from each other.
A. offer B. are offered C. have offered D. are offering
—Your city looks beautiful!
—Yes.Lots of trees and grass last year.
A.are planted B.have planted C.were planting D.were planted
My mother told me that my homework must on time.
finish B. be finish C. be finished D. finished
（三）情态动词
一、语法概述
情态动词表示说话人对所述动作或状态的态度或看法。情态动词一般没有人称和数的变化，在句中不能单独作谓语，必须和动词原形连用。初中阶段常用的情态动词有 can/could、may/might、must/have to、 should/ought to、would、need 等。
二、情态动词的基本用法
情态动词 用法 例句
can/could 表示能力，意为＂能，会＂ I can read this sentence in English. 我能用英语读这 句话。
表示许可时，意为＂可以，能够＂， 相当于 may She said that I could use her computer. 她说我可以使 用她的电脑。
用于推测，表示可能性，意为＂可能＂，could 比 can 更加不肯定，多用于否定或疑问句 The man can’t be our teacher — he has gone to Beijing. 那个男人不可能是我们的老师，他去北京了。 There is someone outside — who can it be 有人在外 面，可能是谁呢？
【知识拓展】 can 的一般疑问句，肯定回答用 Yes, ...can；否定回答用 No, ...can’t。 —Can you play the piano 你会弹钢琴吗 —Yes, I can. 是的，我会。/No, I can’t 不，我不会。 2. can，could 和 be able to 的区别：can 只有现在式和过去式，而 be able to 可以用于各种
时态；can( could)表示能力时，可用 be able to 代替。 I can(am able to) afford the car. 我能买得起这辆小汽车。 She has been able to come to school. 她已经能去学校了 I could(=was able to) drive a car before I left school. 毕业前我就会开车。
may/might 表示允许或许可，意为＂可以＂ May I use your phone 我可以用用你的电话吗？
表示征询许可时，might 比 may 的语气委婉 —Might I ask for a photograph of your little daughter 我能要一张你小女儿的照片吗 —Yes, you may. 是的，你可以。
用于表推测时，是＂可能，或许＂之意，might 语气更加不肯定，多用于 肯定句 He may be wrong, but I’m not sure. 也许他错了，但我也不确定。 She might be very busy now. 她现在可能非常忙。
【知识拓展】 may 的一般疑问句，肯定回答用 Yes, ...may. /Yes, of course. /Yes, certainly.；否定回答用 No, ...can’t/mustn’t。 —Might/May I smoke in this room 我可以在这间屋子里抽烟吗 —Yes, you may. 是的，你可以。/No, you can’t/mustn’t. 不，不可以。 用于表示推测时，may 和 might 一般不用于疑问句，而在疑问句中，常使用 can；在否定句中，may not/might not 意为＂可能不＂，而 can’t/couldn’t 意为＂不可能＂。 The young people might not like the idea. 年轻人可能不喜欢这个主意。 It can’t/couldn’t be our headmaster. He has gone to America. 那人不可能是我们校长。他已经去美国了。
must 表示必须，一定要，指说话人的主观语气 You must obey the school rules. 你必须遵守校 规。
mustn’t 表示禁止，意为＂千万不要，禁止＂，是说话人强有力的劝告 You mustn’t play with the knife or you may hurt yourself. 你禁止玩刀否则你可能会伤到自己。
表示推测时，用于肯定句，意为＂想必，一定＂，否定句中用 can’t/couldn’t 来代替 This must be your room. 这一定是你的房间。 He must be eighty now. 他现在想必有八十岁了。
【知识拓展】 must 的一般疑问句，肯定回答为 Yes, ...must.；否定回答为 No, ...needn’t./No, ...don’t have to. —Must I clean the classroom now 我必须现在打扫教室吗？ —Yes, you must. 是的，你必须。/No, you don’t have to. /No, you needn’t. 不，你不必。 2. must 和 have to 的区别： ①用 must 表示＂必须＂的意思时，通常着重于说话者的主观看法，认为有必要去做某事；而 have to 着重于客观需要，含有＂不得不＂的意思。 We must study English hard. 我们必须努力学习英语。 You are ill today. You have to see a doctor. 你今天病了，不得不去看医生。 ②用 must 表示＂必须＂，只有现在时态的形式，如果要表示过去时或将来时的＂必须＂，就要用 have to 的相应形式。 You must drive fast to catch the time. 你必须开车开快点来赶时间。 They will have to leave tomorrow morning. 他们必须明天早晨起程。
would 作为 will 的过去式，可表示过去的意志、愿望或决心等，意为＂愿意＂ He promised he would never smoke again. 他承诺他再也不吸烟了。
表示过去反复发生的动作或某种倾向 Their English teacher would tell them stories in English after class. 他们的英语老师总是在课 后用英语给他们讲故事。
用于第二人称疑问句中，表示现在的请求、建议，比 will 的语气委婉 Would you please pass the English-Chinese dictionary on to Mary 请把这本英汉词典传 给玛丽好吗
【知识拓展】 would like 意为＂愿意，想要＂； would like/love to do sth 意为＂愿意/想要做某事＂； would like sb to do sth 意为＂想要某人做某事＂。 Would you like a cup of tea 你想喝杯茶吗？ Would you like to sing a song 你想唱首歌吗？
I would like you to wake me up at 5:30 tomorrow morning. 我想让你在明天早晨 5:30 叫 醒我。
should shall 的过去式，用于第一、三人称，多用于间接引语中，以征求对方意见 I asked the manager if I should have a few days off. 我问经理我是否可以请几天假。
表示义务，职责时，意为＂应当，应该＂，往往表示说话者的观点
表示惊讶、遗憾等，意为＂竟然，居然＂
need 表示＂需要，必须＂，多用于疑问句和否定句 Need you go so soon 你需要这么早走吗 You needn’t come so early. 你不必来这么早。
【知识拓展】 need 的一般疑问句，肯定回答为 Yes, ... must.；否定回答为 No, ... needn’t. —Need he finish the article next week 他需要下星期完成这篇文章吗 —Yes, he must. 是的，他必须完成。/No , he needn’t. 不，他不需要。
have to 表示不得不，说明客观条件只能如此；有时态形式的变化；否定式 don’t have to 意为＂不必＂(= needn’t) My brother was very ill, so I had to call the doctor in the midnight. 我弟弟病得厉害，我只得半夜里把医生请来。 I haven’t got any money with me, so I’ll have to borrow some from my friend. 我身上没带钱，只好向朋友借点了。
语法小测
一、单项选择
—Mary,where is Paul
—He a speech on Western art to the first-year students in the hall.
A.gives B.gave C.is giving D.has given
Paul is a foreign teacher in our school.So far, he for over four years.
A.was teaching B.has taught C.will teach D.taught
So far this year, the government many new houses in Wenchuan.
A.build B.are built C.will build D.has built
—Can sixteen-year-olds drive their cars to school
—No.They shouldn’t to drive because they are not serious enough.
A.allow B.allowed C.be allowed D.have allowed
My sister Qingdao two years ago, she for two years.
A. has left; has left B. left; has been away
C. left; has left D.has left; left
I the History Museum twice. I've learned a lot there.
A. visit B. am visiting C. have visited D. will visit
— I return the book today, Mr. Lin
—No, you . You can keep it for two days.
A. May; mustn’t B. Must; mustn’t C. Must; needn’t D. Can; shouldn’t
The dictionary at the Lost and Found office be Tim’s, because his name is on its corner.
A. can B. can’t C. must D. mustn’t
This kind of pen and is also very cheap. I think you can buy some.
A.writes well B.writes good C.is written well D.is written good
10.—Do you know the famous artist in red
—Sure. He to the art festival in our city every year.
A.invites B.invited C.is invited D.was invited
—Look! The man at the gate be our headmaster. He is always standing there every morning.
—No, it be him. He is holding a meeting in the office now.
A. must; can’t B. must; mustn’t C. can’t; can’t D. can’t; mustn’t
Paper first about 2000 years ago in China.
A. is; creating B. is; created C. has; created D. was; created
There's only one day to go. You finish your schoolwork by tomorrow.
A. can B. may C. will D. must
I won’t go to her party unless my best friend Jack .
A. will invite B. will be invited
C. is invited D. invites
15.---Is that man Mr. Smith
--- It be him. He has gone to New York on business.
A. can’t B. may not C. mustn’t D. needn’t
二、动词应用（根据短文内容,用括号内所给动词的适当形式填空,必要时可加助动词或情态动词。）
Scientists are trying 1. (make) deserts into good land again. They want 2. (bring) water to the deserts, so people can grow crops and 3. _______(live) there. They 4. _______(learn) a lot about the deserts. But more and more of the earth is 5. _________(become) deserts all the time.
Why is this true Scientists think that people are making deserts. People are doing bad things to the earth.
Some places on the earth 6. (not have) much rain, but they don’t become deserts. This is because some green plants are growing there. Small green plants and grass 7. (be) very important to dry places. Plants prevent the sun from 8. (make) the earth drier. Plants prevent the wind from blowing the earth away. When a little bit of rain 9. ________(fall), the plants hold the water. Without plants, the lands 10._________(become) deserts easily.
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