内容正文:
Unit 3 Work It Out Together
专题02 语法提升·易错题专项训练
高频易错点03 动词短语 work out /figure out 用法
高频易错点01 情态动词 must 与 have to 的辨析
高频易错点02 提建议句型(Why not… / Why don’t you… / Let’s…)
高频易错点、易错点提示、小练笔、答题点拨
易错精讲
情态动词 must 与 have to 的辨析高频易错点01
表① must:表示主观上的 “必须”,是说话人内心觉得有必要。属于情态动词,后面只能接动词原形,
无人称和数的变化。
肯定:主语 + must + 动词原形
否定:主语 + mustn’t + 动词原形(mustn’t 表示禁止,不许)
例句:You must work together. 你们必须一起合作。 You mustn’t give up. 你不许放弃。
② have to:表示客观情况造成的 “不得不”,受外界条件、规则影响。有人称变化,三单用has to。
肯定:I/You/We/They + have to + 动词原形;He/She/It + has to + 动词原形
否定:don’t/doesn’t have to(表示 “不必”,不是禁止)
例句:We have to work out this problem together. 我们不得不一起解决这个难题。
He has to finish the task today. 他今天不得不完成这项任务。
易错点提示
must 没有人称变化,不管主语是谁,都直接用 must + 动词原形,不能写成 musts。
错误:He musts try his best. 正确:He must try his best.
注意否定含义区分,极易混淆:
mustn’t = 禁止,不许(绝对不可以做)
don’t/doesn’t have to = 不必(没有必要做,可以不做)
例:You mustn’t run in the hall. 不许在走廊奔跑。 You don’t have to join us. 你不必加入我们。
have to 有人称变化,主语 he/she/ 单数名词用 has to;疑问句要借助助动词 do/does,
不能直接把 have to 提前。 错误:Has he to help? 正确:Does he have to help?
小练笔
一、单项选择
( )1. You ______ give up. We can work it out together.
A. must B. mustn’t C. don’t have to
( )2. Tom ______ finish the project before Friday. It’s the rule.
A. must B. has to C. have to
( )3. —______ I clean the room now? —No, you ______. You can do it later.
A. Must; don’t have to B. Must; mustn’t C. Have to; mustn’t
( )4. You ______ shout in the library. It’s against the rule.
A. don’t have to B. mustn’t C. haven’t to
( )5. She ______ work with her classmates to solve the hard problem.
A. must B. musts C. have to
二、用括号内所给词的适当形式填空
1.We must ______ (try) our best to work out the problem.
2.He has to ______ (talk) with his group members.
3.You ______ (must) copy others’ homework. It’s wrong.
4.They don’t ______ (have to) finish it today.
5.Lily ______ (have to) ask for help when she meets difficulties.
点拨
一、
1. B
解析:句意:你不许放弃,我们可以一起解决。mustn’t 表示禁止、不许,故选 B。
2. B
解析:rule 规则,属于客观外界要求,主语 Tom 三单,用 has to “不得不”,故选 B。
3. A
解析:Must 引导问句;否定回答不必做,用 don’t have to,而 mustn’t 表示禁止,不符合
语境,故选 A。
4.B
解析:图书馆不许大喊,mustn’t 表示禁止,故选 B。
4. A
解析:must 情态动词无人称变化,后面接动词原形;主语 she 三单,have to 要改为 has to,
C 形式错误,故选 A。
2、 用括号内所给词的适当形式填空
1. try
解析:must 情态动词后接动词原形。
2. talk
解析:has to 后面接动词原形。
3. mustn’t
解析:句意:你不许抄别人作业,这是错的,mustn’t 表禁止。
4. have to
解析:don’t 后面动词还原,用 have to。
5. has to
解析:主语 Lily 是第三人称单数,have to 变为 has to。
提建议句型(Why not… / Why don’t you… / Let’s…)高频易错点02
本单元用于小组合作,提出解决问题的建议,三种核心句型:
1.Why not + 动词原形? 为什么不…… 呢?(Why not = Why don’t you)
例:Why not work it out together? 为什么不一起把它解决呢?
2.Why don’t you + 动词原形? 你为什么不…… 呢?
例:Why don’t you ask your group for help? 你为什么不向小组寻求帮助?
3.Let’s + 动词原形 让我们……(第一人称复数提建议)
否定:Let’s not + 动词原形 让我们不要……
易错点提示
1. Why not 后面直接加动词原形,不能加 to,不能加 you。
错误:Why not you to try? 正确:Why not try?
2. Why don’t you 句子成分不能丢,don’t 不能写成 not。
错误:Why not you work together? 正确:Why don’t you work together?
3. Let’s 后只能接动词原形;否定结构是 Let’s not do,不能用 don’t。
错误:Let’s don’t give up. 正确:Let’s not give up.
小练笔
一、单项选择
( )1. ______ work out the problem together?
A. Why not B. Why not you C. Why don’t
( )2. ______ ask your partners for some good ideas.
A. Why not you B. Why don’t you C. Why you not
( )3. Let’s ______ a plan for our group project.
A. make B. to make C. making
( )4. ______ be lazy. We need to finish our task.
A. Let’s not B. Let’s don’t C. Not let’s
( )5. —I can’t solve this problem. —______ try again?
A. Why not B. Why not to C. Why don’t
二、按要求改写句子
1.You should work together.(改为 Why not 句型)
______ ______ work together.
2. Why don’t you talk it over?(改为同义句)
______ ______ talk it over.
3. Let’s think of new ideas.(改为否定句)
______ ______ think of new ideas.
4. Why not give him a hand?(改为 Why don’t you 句型)
______ ______ ______ give him a hand?
点拨
一、1.A
解析:Why not + 动词原形,用于提建议,故选 A。
2. B
解析:Why don’t you + 动词原形,为固定提建议句型,故选 B。
3. A
解析:Let’s 后面接动词原形 make,故选 A。
4. A
解析:Let’s not + 动词原形,是 Let’s 的否定形式,故选 A。
5. A
解析:Why not 后直接接动词原形,故选 A。
二、按要求改写句子
1.Why not
解析:Why not 后面直接接动词原形。
2. Why not
解析:Why not = Why don’t you,同义转换。
3. Let’s not
解析:Let’s 的否定为 Let’s not + 动词原形。
4. Why don’t you
解析:Why don’t you + 动词原形,固定句型。
高频易错点03
动词短语 work out /figure out 用法
work out /figure out + 名词:解决,弄明白,算出(难题、问题);代词作宾语,只能放中间:work it out,不能说 work out it。
例句:
We work out the difficult problem. 我们解决这个难题。
We work it out together. 我们一起把它解决。
易错点提示
1. 代词 it/them 必须放在短语中间,名词可以放中间或者后面。
错误:Let’s work out it. 正确:Let’s work it out. 正确:work out the problem = work the problem out
2. 不要遗漏 out;work 单独使用是 “工作”;work out 才表示解决难题。
错误:Let’s work the problem. 正确:Let’s work out the problem.
小练笔
一、单项选择
( )1. This is a hard question. Let’s ______.
A. work out it B. work it out C. work it
( )2. They can’t ______ the answer by themselves.
A. work out B. work C. figure
( )3. These problems are too hard. We must ______ together.
A. work them out B. work out them C. work them
( )4. Can you ______ this puzzle?
A. work out B. work on C. work for
( )5. Don’t worry. We will ______.
A. figure out it B. figure it out C. figure it
二、用括号内短语的适当形式填空
1.Let’s ______ (work out) this maths problem.
2.This task is difficult. We need to ______ (work out it) together.
3.Can you ______ (figure out) the secret?
4.These riddles are hard. Can you ______ (figure out them)?
点拨
一、
1. B
解析:代词 it 放在 work 和 out 中间,work it out 解决它,故选 B。
2. A
解析:work out 表示算出、解决,故选 A。
3. A
解析:代词 them 放中间,work them out,故选 A。
4. A
解析:work out 表示解开(谜题),故选 A。
5. B
解析:代词 it 放在 figure 与 out 中间,figure it out 弄明白,故选 B。
二、用括号内短语的适当形式填空
1.work out
解析:宾语是名词 problem,可以直接放短语后面。
2.work it out
解析:代词 it 放中间。
3. figure out
解析:宾语是名词 secret,放短语后面。
4. figure them out
解析:代词 them 放中间
综合训练
一、单项选择
1.You ______ talk loudly in the reading room. It’s the rule. ( )
A. mustn’t B. don’t have to C. must
2.—I can’t finish this task. —______ ask your group members for help? ( )
A. Why not B. Why not you C. Why don’t
3.He ______ stay at home and finish his project, because his teacher asks him to. ( )
A. must B. has to C. have to
4.The problem is hard. Let’s ______ together. ( )
A. work it out B. work out it C. work it
5.—Must I join the group work now? —No, you ______. You can join us later. ( )
A. mustn’t B. don’t have to C. can’t
6.______ give up. We still have time. ( )
A. Let’s not B. Let’s don’t C. Not let’s
7.Why ______ think of a new way to solve the problem? ( )
A. not you B. don’t you C. not to
8.They ______ work together. That’s the group rule. ( )
A. must B. musts C. have
9.We don’t ______ finish all work today. We can do part of it tomorrow. ( )
A. have to B. must C. mustn’t
10.This riddle is very hard. Can you ______? ( )
A. figure out it B. figure it out C. figure it
二、用所给词的适当形式填空
1.You must ______ (cooperate) with your partners.
2.She has to ______ (share) her ideas with the group.
3.You ______ (must) copy others’ answers. It is bad.
4.Let’s ______ (not give) up. We can work it out.
5.They ______ (have to) work out these puzzles in class.
三、句型转换
1.You must work together to solve the problem.(改为否定句)
_________________________________________________
2.Why not try this new idea?(改为同义句)
_________________________________________________
3.We can work out that hard question.(用代词改写划线部分)
_________________________________________________
4.He has to finish the task before dinner.(改为一般疑问句)
_________________________________________________
5.Let’s discuss our plan.(改为否定句)
_________________________________________________
四、补全短文。根据上下文,用括号内所给单词的适当形式填空,每空一词。
Today we have a difficult group task. We 1______ (must) finish it in class. Tom says we 2______ (have to) think hard. Lily says “ 3______ (why not) work together?” We 4______ (mustn’t) give up. We try different ways. At last, we 5______ (work out) it together. We feel very happy.
五、阅读短文,完成题目。
Group work is fun but sometimes difficult. When you meet hard problems in group work, what can you do? First, you must listen to your partners’ ideas. You mustn’t only think of yourself. You don’t have to agree with everyone, but you should respect (尊重) them. Why not share your own ideas? If you can’t solve the problem alone, you have to work it out together. Good teamwork helps you finish tasks quickly.
1. 阅读短文,选择最佳的选项。
(1) What must you do in group work? ( )
A. You must listen to your partners’ ideas. B. You must always agree with everyone.
C. You must work alone all the time.
(2) What mustn’t you do? ( )
A. Share your ideas. B. Only think of yourself. C. Respect your partners.
(3) If you can’t solve the problem alone, you ______. ( )
A. have to work it out together B. must give up at once C. don’t have to do anything
(4) Which sentence is TRUE? ( )
A. Good teamwork helps finish tasks quickly. B. You mustn’t share your ideas.
C. You have to agree with all partners.
2.阅读短文,回答问题。
(1) What can you do when you meet hard problems in group work?
_________________________________________________
(2) What will you do in your group work?(根据实际情况回答)
_________________________________________________
参考答案
一、单项选择
1.A
【详解】句意:在阅览室你不许大声讲话,这是规定。mustn’t 表示禁止不许,故选 A。
2. A
【详解】句意:— 我完不成这项任务。— 为什么不向组员求助?Why not + 动词原形,提建议,故选 A。
3. B
【详解】句意:他不得不待在家完成项目,因为老师要求他。外界客观要求,主语 he 三单,用 has to,故选 B。
4. A
【详解】句意:这个问题很难,让我们一起把它解决。代词 it 放 work 与 out 中间,work it out,故选 A。
5. B
【详解】句意:— 我现在必须参加小组活动吗?— 不必,你可以晚点加入。must 问句否定回答用 don’t have to,故选 B。
6. A
【详解】句意:我们不要放弃,我们还有时间。Let’s not + 动词原形,故选 A。
7. B
【详解】句意:你为什么不想一个新办法解决这个问题?Why don’t you + 动词原形,故选 B。
8. A
【详解】句意:他们必须合作,这是小组规则。must 情态动词无人称变化,故选 A。
9. A
【详解】句意:我们不必今天做完所有工作,我们可以明天做一部分。don’t have to 不必,故选 A。
10. B
【详解】句意:这个谜语很难,你能弄明白吗?代词 it 放在 figure 和 out 中间,figure it out,故选 B。
二、用所给词的适当形式填空
1.cooperate
【详解】must 后面接动词原形 cooperate。故答案为 cooperate。
2. share
【详解】has to 后面接动词原形 share。故答案为 share。
3. mustn’t
【详解】句意:你不许抄别人的答案,这样不对。mustn’t 表禁止。故答案为 mustn’t。
4. not give
【详解】Let’s not + 动词原形。故答案为 not give。
5.have to
【详解】主语 they 是复数,用 have to。故答案为 have to。
三、句型转换
1.You mustn’t work together to solve the problem.
【详解】must 的否定直接在后面加 not,变为 mustn’t。
2.Why don’t you try this new idea?
【详解】Why not do = Why don’t you do,同义转换。
3.We can work it out.
【详解】代词 it 代替 that hard question,代词放短语中间。
4.Does he have to finish the task before dinner?
【详解】have to 的疑问句借助助动词 does,has 变回原形 have to。
5.Let’s not discuss our plan.
【详解】Let’s 的否定:Let’s not + 动词原形。
四、补全短文
1.must
解析:情态动词 must 无人称变化。
2.have to
解析:主语 we 复数,用 have to。
3.Why not
解析:句首大写,Why not 提建议。
4.mustn’t
解析:句意:我们不许放弃。
5.work it out
解析:代词 it 放中间。
五、阅读短文
1.(1) A (2) B (3) A (4) A
【详解】
(1) 文中 “you must listen to your partners’ ideas”,选 A。
(2) 文中 “You mustn’t only think of yourself.”,选 B。
(3) 文中 “If you can’t solve the problem alone, you have to work it out together.”,选 A。
(4) 文中 “Good teamwork helps you finish tasks quickly.”,选 A。
2.
(1) I can listen to my partners’ ideas, share my ideas and work it out together.
(2) 示例:I will listen to my partners and share my ideas in group work.(答案不唯一)
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