Unit1Grammar 知识点练习-2021-2022学年外研版（2019）高中英语必修二

Unit 2 Grammar-Modals can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would) . ①modal verbs(only)：must, can, may…… ②modal verbs/notional verbs：need, will, dare ③has the characteristics of modal verbs：have(had, has) to, used to, ought to ④modal verb or an auxiliary verb：shall(should), will(would) I. Definition Modal verbs express the speaker's mood, such as “possible, speculation, obligation, need, etc”. Modal verbs have the following characteristics: 1. Has a certain sense of meaning, but can not be used as a predicate alone, followed by a verb base form. 2. There are no person and number changes (except have to). 3. Most modal verbs have past tense such as can-could, may-might, will - would, dare - dared etc. (The "tense" of a modal verb is not the main distinguishing mark of time. In many cases, both the base form and the past tense of a modal verb can be used in a variety of tenses.) II. Usage 1．can与could的用法 (1)表示能力，常译为“能，会”。could是can的过去式，表示过去的能力。 ◆I can speak English and French, but I can’t speak Japanese. ◆When she was 8 years old, she could play the piano very well. (2)表示许可或请求(在陈述句中属于“许可”，在疑问句中属于“请求”)，常译为“可以”；could比can的语气更加委婉。 ◆—Can/Could I use your computer？(请求允许) —Of course, you can.(表示允许) (3)表示推测，意为“可能”，常用于否定句和疑问句中。 ◆—Can the lady over there be our boss? —It can’t be her.I saw our boss in the office just now. ◆My glasses aren’t here.Where can I have put them? (4)表示理论上或习惯上的可能性，意为“可能会”。 ◆Jogging can be beneficial to the health. can (1)单纯地表示一个人有某种能力； (2)只有过去式could be able to (1)表示某人通过努力、克服困难做成某事； (2)可用于各种时态 ◆He could swim when he was five years old. ◆After years of hard work he was able to win the prize. 2．must与have to的用法 (1)must表示义务、必要性、命令等，意为“必须，应该”，更强调主观态度。 ①must用于一般疑问句时，其肯定答语应用“Yes, you must.”。其否定答语应用“No, you needn’t.”或“No, you don’t have to.”。 ②must的否定式为must not/mustn’t，表示禁止。 ◆The law states that people mustn’t drive after drinking alcohol. ◆—Must I finish the work tomorrow? —Yes, you must.(No, you n