Unit 1 Section Ⅱ Using language—Grammar(Word教参)-【优化指导】2022-2023学年新教材高中英语必修第二册（外研版2019）

Section Ⅱ　Using language—Grammar 情态动词(1) [对应学生用书P12] [观察] 1．...ever since I was able to hold a knife and fork—and chopsticks! 2．But there are still some dishes that Dad dare not try even after many years of marriage to my mother. 3．...Mum and I just have to find a way to get him into the kitchen! 4．...we'd better not eat too much roast food as it may make us suffer from heat inside our bodies ... 5．“You needn't try it if you don't want to，” Mum said ... [归纳] 1．例句1、3中分别含有情态动词be able to“能够”和 have to“不得不”，其后接动词原形，有时态、人称和数的变化。 2．例句2、4、5 中分别含有情态动词 dare“胆敢，敢于”，had better“最好”和need“需要”，其后接动词原形，其否定形式直接加not，没有时态、人称和数的变化。 [对应学生用书P12] 一、be able to“能够” 后接动词原形，表示某人做某事的能力，be动词有时态、人称和数的变化，不能与can连用。 He will be able to sing this song in English in a few minutes. 几分钟之后，他能用英语唱这首歌。 It took Daniel a long time before he was able to fully appreciate what I had done for him. 丹尼尔过了好久才能完全理解我为他做的事情。 二、have to“不得不” 后接动词原形，可用于各种时态，have有时态、人称和数的变化。 We don't have to be hurry—there's plenty of time. 我们不必着急——有很多时间。 Lucy has to pass an exam before she can get the work. 露西必须通过考试才能得到这份工作。 Yesterday afternoon I had to visit a friend. 昨天下午我不得不去拜访了一个朋友。 —Do you have to look after your brother? —Yes, I do./No, I don't. ——你得照看你弟弟吗？ ——是的，我得照看。/不，我不必照看。 Why does John have to move to London? 约翰为什么不得不搬往伦敦？ ①have to的陈述句形式 肯定形式： have to＋动词原形 否定形式：don't/doesn't/didn't＋have to＋动词原形 ②have to 的一般疑问句形式必须把助动词do或does提到句首。 ③have to的特殊疑问句形式 特殊疑问词＋do/does/did＋sb.＋have to ...？ 　must/have to 意义 否定形式 must 强调说话者的主观意愿。 He said that he must finish the work on time. 他说他必须按时完成工作。 mustn't，意为“不许，不可以”，表示禁止。 You mustn't smoke in the waiting room. 禁止在等待室吸烟。 have to 强调客观上的必要性。 The last bus left, and he had to walk home. 最后一班车走了，他只好步行回家。 not have to，意为“不必”，相当于needn't。 You don't have to finish the task today. 你今天不必完成这项任务。 三、had better“最好” 后接动词原形，其中的had常缩略为'd；否定形式是had better not；疑问形式则通常将had置于主语之前。 You had better not go there by train. 你最好不要乘火车去那里。 Who had we better ask for help? 我们最好向谁求助？ 四、dare“敢于，胆敢” 作情态动词时常用于疑问句、否定句及条件句中