Unit 1 Section 3 Grammar—情态动词(1)-【赢在微点】轻松课堂2023-2024学年新教材高中英语必修第二册（外研版）

Section 3　Grammar—情态动词(1) 语法图解 观察句子 1.Mum and I just have to find a way to get him into the kitchen! 2.Dare you go swimming alone in the river? 3.My foreign friend dare not try stinky tofu. 4.You needn􀆳t finish reading the book today. 5.Need I clean the room right now? 6.I was able to organize the meeting successfully. 7.I􀆳d better go home by bus as it is raining hard. 我的领悟 1.be able to、had better、have to、dare和need后都接动词原形。 2. 情态动词dare 和need 常用于否定句和疑问句中, 如句2、句3、句4和句5。 一、be able to 和had better 1.be able to be able to表“能够”,其后接动词原形,be有时态和人称变化,可与情态动词will, would, shall, should连用。 ①He is ill. He hasn􀆳t been able to go to school for a week.他病了,已经有一周没上学了。 ②I􀆳ll be able to help you tomorrow.我明天能帮助你。 微点　叙述过去经过一番努力才能完成的事情时,用was/were able to,不可以用could。表一般的能够做某事的能力,两者可互相替换。 Mary can/is able to type well. 玛丽打字打得很好。 He was able to swim well after practicing hard. 刻苦训练后他能游得很好了。 2.had better had better 意为“最好”,缩写形式是􀆳d better。 had better 只有一种形式,不能单独作谓语,后面跟动词原形, had不能用has或have代替。 ①He had better learn a second language.他最好学一门外语。 ②You􀆳d better not ask those confusing questions.你最好别问那些令人困惑的问题。 二、have to have to/don􀆳t have to have to表示客观上的必要性,意为“不得不”。它有多种时态变化形式,其疑问式和否定式通过添加助动词do/does/did构成。have to与have got to常可以互换。 ①The washing machine is out of order, so I have to wash the clothes by hand.洗衣机坏了,因此,我不得不手洗衣物。 ②He had to get up early last Sunday.上周日他不得不早起。 ③Do you have to stay in that room for so long?你必须待在那个房间里那么久吗? 微点　must与have to表示“必须”时的区别: (1)must 表示一种主观上的需要,而have to 表示一种客观上的需要,意思是“不得不”。 I have to attend an important meeting this afternoon.今天下午我不得不参加一个重要的会议。 You must do as you are told.你必须遵嘱行事。 (2)don􀆳t have to 表示没有义务或必要做某事,相当于needn􀆳t,常可以用来回答must开头的疑问句,与mustn􀆳t 的含义完全不同。前者意为“不必;不需要”,后者意为“不许;不应当;一定不要;绝不要”。 You don􀆳t have to worry about your lessons.你没必要为你的功课担心。 They don􀆳t have to buy a computer at present.他们目前没有必要买电脑。 You mustn􀆳t drive fast.你一定不要开快车。 【微练1】　完成句子 ①You􀆳d better be quiet.  你最好安静点。 ②Next year you will have to finish your schooling.  明年你必须结束学业。 ③Last week we ha