Unit 1 Food for thought语法-精讲破
一、be able to的用法
观察
Since his accident he hasn't been able to leave the house.
自出事之后,他一直未能离开这座房子。
You might be able to persuade him.
你也许能够说服他。
I hope to be able to do the work.
我希望能做这项工作。
I regret not being able to help her.
我很遗憾未能帮助她
The road was so narrow that cars were unable to pass.
这条路太窄了,汽车过不去。
归纳
(1)be able to意为“能够,有能力”,不仅有①_________、②_________和数的变化,而且还可以与某些情态动词连用(通常不与can连用),甚至还可以有非谓语动词形式。
(2)able的反义词为unable。
易混辨析
can和be able to都可以表示能力,前者表示主语原本就具有某种能力,后者表示通过努力可以具备某种能力或实现某种状态,重点强调的是要有一个努力的过程。如:
I can play the piano.(隐含着“我本来就会弹钢琴”的意思)
I am able to play the piano.(隐含着“我只要努力就有能力学会弹钢琴”的意思)
链接高考
单句语法填空
1.(2020全国新高考I,阅读理解B)She chose the UW-Eau Claire program at Ministry Saint Joseph's Hospital in Marshfield because she was able________ (pursue) her four-year degree close to home.
2.(2020全国Ⅲ,阅读理解C)With the young________(able) to afford to leave home and the old at risk of isolation(孤独), more families are choosing to live together.
3.(2019北京,完形填空)For many students,Wilson's help is not only appreciated, it's also entirely necessary for them to be able ________ (complete) their college education.
4.(2019北京,阅读理解B)Meanwhile, with her parents' help, Moore is generally able to________(live) a normal teenage life.
5.(2019课标全国Ⅱ,阅读理解B)The coach________(be) able to focus on the kids while the other parents are relieved to be off the hook for another season.
二、dare的用法
观察
Dare you climb that tree?
你敢爬那棵树吗?
He daren't go there because it is very dangerous.
他不敢去那儿,因为那儿很危险。
If he dare hit me below the belt, I won't put anything past him.
如果他胆敢给我使坏,我将饶不了他。
She didn't dare to go there alone, because it was too late.
她不敢独自一人去那儿,因为太晚了。
归纳
(1)dare既可作情态动词,也可作实义动词;
(2)dare作③_________时,表示“敢,敢于”,后跟④_________,常
用于疑问句、否定句和条件句中。此时的dare没有人称和数的变化;
(3)dare用作⑤_________时,有时态和人称的变化,其后多跟带to的不定式。
链接高考
单句语法填空
6.(2020天津,阅读理解B)I wouldn't have dared_________(ask)you, but my teacher, Mr. Mills, says I am ready.
完成句子
7.(2019天津,阅读理解D改编)那些敢于尝试的人经常使自己陷入困境。
Those who _________ _________often get themselves trapped.
8.(2017浙江,读后续写)但赤手空拳,他们不敢与狼搏斗。
But with the bare hands, they _________ _________ _________ _________ with the wolf.
三、have to的用法
观察
It's too late. I have to go home now.
天色太晚了,我现在得回家了。
She has to work within the limits of a fairly tight budget.
她不得不在相当紧张的预算范围内工作。
You don't have to get dressed up for this party.
你不必为这次聚会而穿盛装。
归纳
have to意为“不得不,必须”,有时态、人称和数的变化;其否定形式为don't/doesn't/didn't have to,意为“不必”。
易混辨析
have to和must的区别:
⑥_________表示一种客观的需要,而⑦_________表示一种主观的需要。
链接高考
单句语法填空
9.(2016四川,短文改错)Mom has a full-time job, but she _________ (have)to do most of the housework.
句式转换
10.(2020天津5月,13)The1ocal government has to sacrifice environmental protection to promote economic growth.(改为否定句)
→The local government _________ _________ _________ sacrifice environmental protection to promote economic growth.
四、had better的用法
观察
She'd better get here soon or she'll miss the opening ceremony.
她最好快点到这儿来,否则她会错过开幕式的。
They had better not be late.
他们最好不要迟到。
归纳
had better意为“最好:应该”,后跟动词原形,常用来提出建议,或表示迫切的希望、警告等,语气较强。其中had没有人称和数的变化。had better的简略式为:'d better,否定式为:⑧_________。
链接高考
完成句子
11.(2016课标全国Ⅲ,七选五)当你买了一条鱼回家后,如果不马上做它
的话,你最好把鱼储存在冰箱里……
When you have bought a fish and arrive home, _________ _________ _________ the fish in the refrigerator if you don't cook it immediately...
五、need的用法
观察
-Need I finish the work today
-Yes, you must./No, you needn't.
—我需要今天干完这活吗?
—是的,你必须干完。/不,你不必干完。
You needn't book the tickets in advance.
你不必提前订票。
The bike needs repairing.
=The bike needs to be repaired.这辆自行车需要修理。
归纳
(1)need意为“需要”,既可作情态动词,也可作实义动词:
(2)need作⑨_________时,常用于疑问句和否定句中,其否定形式为needn't; need作⑩_________时,后可接名词、动名词、不定式等,有人称、时态和数的变化。
链接高考
单句语法填空
12.(2020浙江1月,语法填空)A child born in the US today has a very realistic chance of living beyond 100 and needs_________(plan)accordingly.
13.(2020浙江,语法填空)And, as more children were born, more food _________(need).
14.(2017天津,2)My room is a mess, but I needn't _________ (clean)it before I go out tonight.
参考答案:
①时态 ②人称 ③情态动词 ④动词原形 ⑤实义 ⑦动词 ⑥have to ⑦must ⑧had better not ⑨情态动词 ⑩实义动词
l.to pursue考查动词不定式。此处表示“她可以在离家近的地方攻读四年学位”。be able to do sth.能够做某事,故填to pursue。
2.unable考查词形转换。句意:由于年轻人无力负担离开家的费用,老年人面临着被孤立的风险,更多的家庭选择住在一起。根据choosing to live together可知年轻人“无力负担离开家的费用”,此处应用able的否定形式,be unable to do sth.不能做某事,故填unable。
3.to complete考查不定式。此处表示“对他们能够完成大学教育也是完全必要的”,be able to do sth.意为“能够做某事”,故此处应用不定式to complete。
4.live考查动词形式。句意:同时,Moore在她的父母的帮助下,大致能够过上正常的青少年生活。be able to后跟动词原形,故本空应用动词原形live。
5.is考查时态。句意:教练能够将注意力集中在孩子身上,而其他家长们因为又一个赛季不用操心而松了口气。本句为while连接的并列复合句,根据后面的分句中are可知,本空应用一般现在时。
6.to ask考查dare的用法。句意:我本不敢问你,但我的老师米尔斯先生说我准备好了。dare作实义动词时,其后多跟带to的不定式,故填to ask。
7.dare try
8.didn't dare to fight
9.has考查时态。句意:妈妈有一份全职工作,但她必须做大部分家务。本句为but连接的并列复合句,根据前面的分句的谓语has可知,本空应用一般现在时。
10.doesn't have to
11.you'd better store
l2.to plan考查need的用法。句意:如今在美国出生的孩子有切实的机会活到100岁以上,因此需要做出相应的计划。根据needs可知本句中need是实义动词,后接动词不定式作宾语,故填to plan。
13.was needed考查动词的时态和语态。本句中need是实义动词,结合语境“出生的孩子越多,需要的粮食就越多”可知,more food与need之间构成被动关系,且根据前面的were可知,此处应填was needed。
14.clean考查动词形式。句意:我的房间乱七八糟,但我不必在今晚出去之前打扫它。本句中needn't为情态动词,故本空应用动词原形。
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