Unit 1 Food for Thought Using language 课件-2023-2024学年高一英语外研版（2019）必修第二册

Book 2 Unit 1 Food for thought Using language a ...I was able to hold a knife and fork - and chopsticks! b But there are still some dishes that Dad dare not try even after many years of marriage to my mother. c ...Mum and I just have to find a way to get him into the kitchen! d ...we’d better not eat too much roast food as it may make us suffer from heat inside our bodies, ... e “ You needn’t try it if you don’t want to,” Mum said,... Look at the sentences from the reading passage. Think and work out the meanings of the words underlined. Activity 1 What's the meaning of the underlined words ? Modal verbs(情态动词) can be used to express the speaker’s meaning of ability, possibility, permission, and advice, etc. be afraid to do sth have the ability to do sth be necessary or give strong advice to do sth give advice to do or not to do sth not be necessary to do sth Now let’s focus on more examples. Modal verbs be able to dare＆need have to had better Grammar be able to do sth. = have the ability to do sth. be able to 后接动词原形，表示某人做某事的能力，可用于大多数时态。 be able to 用于过去时态时，可以表示 “某人过去或当时成功地做了某事”。 If I work harder, I will be able to make greater progress. There was a big fire. Luckily, everyone was able to escape. Grammar dare not do sth. = be afraid to do sth. dare 作情态动词时， 没有人称和数的变化，否定式是dare not，主要用于否定句、疑问句和条件从句中，一般不用在肯定句中。 dare 常用作实义动词(即有实际意义的动词，表行为、动作或状态的词，词义完整)，有时态、人称和数的变化。用在肯定句中，dare+带to的不定式；用在否定句和疑问句中，dare+带to/不带to的不定式。 She dare not go out alone at night. She doesn’t dare (to) go out alone at night. Grammar have to 的含义与must相似，两者往往可以互换使用，但have to 有各种时态，且强调客观需要，意为 “不得不”。 否定形式是don’t have to，相当于needn’t。 have to = be necessary or give strong advice to do sth. There were no buses; we had to walk all the way home. You don’t have to/needn’t bring a gift if you don’t want to. Grammar had better 后接动词原形，意为“最好”， 用于现在或将来时，可用于一切人称，没有任何词形变化。 had better 的否定式是在其后加not，疑问式是把had和not 提前。 had better = give advice to do or not to do sth. You’d better think twice before making