UNIT1 Section Ⅳ Grammar-【金版新学案】2023-2024学年新教材高一英语必修第二册同步课堂高效讲义教师用书（外研版2019）

Section Ⅳ　Grammar 情态动词(Ⅰ) [教材示例] 分析下列加黑部分并体会它的语法功能 1．...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... [探究发现] 1．情态动词的基本特征是有一定的词义，不能单独作谓语，需和实义动词或系动词一起作谓语。情态动词后接动词原形。 2．情态动词一般无人称和数的变化，个别情态动词有现在时和过去时两种时态变化。如句1和句3。 3．构成否定句时，not放在情态动词后面。如句2，句4和句5。 1．can与be able to (1)can只有现在时和过去时(could)，而be able to则有更多的时态变化，在将来时、完成时和非谓语动词中只能用be able to。 This time I failed in the exam，but I'll be able to pass the exam next time. 这次我考试不及格，但下次考试我能及格。(将来时) (2)can一般指自身具有的能力，而be able to则表示经过一段时间的努力后所具有的能力，相当于manage to do或succeed in doing。 I can/am able to speak both English and French. 我会说英语和法语。 [名师点津] 现在时can与be able to没有区别，但是在过去时中二者意义不同。 All the people could escape from the burning hotel last night. 昨晚所有的人都有能力从燃烧的旅馆里逃脱出来。(有这种能力，但不一定做到) All the people were able to escape from the burning hotel last night. 昨晚所有的人都从燃烧的旅馆里逃脱出来了。(成功做到了) 学生用书第22页 (3)在否定结构中was/were able to与could没有区别。 She ran fast but she couldn't/wasn't able to catch the bus. 她跑得很快可还是没能赶上公交车。 (4)can/could表示请求别人做某事，意为“能，可以”。 —Can/Could I come to see you tomorrow? —Yes，you can. ——我明天能来看你吗？ ——可以。 (5)can/could表示惊讶，常用在否定句和疑问句中。 How could you do such a silly thing？(表示惊讶) 你怎么能做那样的蠢事呢？ 2．need的用法 (1)need作情态动词时，后跟动词原形，表示“需要，有必要”，无人称和数的变化，多用于疑问句、否定句或条件句中。其否定形式是在其后直接加not，疑问形式是直接将need提到主语前。由need构成的一般疑问句，其肯定回答用must或have to。否定回答常用needn't。 —Need I finish the work today? —Yes，you must/have to./No，you needn't. ——我需要今天干完这项工作吗？ ——是的，你必须干完。/不用，你不必干完。 There's plenty of time.You needn't drive so fast. 时间很充足，你不必开这么快。 (2)作实义动词 need作实义动词时，后可接名词、动词­ing 形式、动词不定式等，有人称、时态和数的变化，其否定形式、疑问形式都要通过助动词do构成。物作主语时need后跟doing或to be done。 There are always people who need help from others. 总会有人需要他人的帮助。 He didn't need to set off so early. 他不必那么