`can、could、may、might、should、ought to、must、have to、need、don't have to、had better、would rather、used to + v、would + v` # can、could * 表示能力，用`be able to`代替can/could現在/過去的能力 * 客觀可能性（can的可能性更大） * 表示請求和允許（could更委婉一些） ``` He can/could/is able to swim. 他能游泳。 He can/could come tomorrow. 他明天能（可能性）來。 Can/Could I stay here? 我能呆在這嗎？ ``` # may、might * 表示可能性（may的可能性更大） * 表示使請求和允許（might更委婉一些） ``` -Yes,please. -No,you can't/mustn't（禁止，不準） He may/might come here by bus. May/Might I join you? -Yes,please./No,you can't./No,you mustn't. ``` # must、have to * 表示必須、必要 * must表示主觀多一些 * have to表示客觀多一些，有“不得不”的意思 * have to有時態和數量的變化 * must和have to二者的否定意義大不相同 * You mustn't go.你不準去。 * You don't have to go.你不必去。 ``` You must get up early.你必須得早點起床。（主觀色彩的必須） It's going to rain,I have to go home now.外面要下雨了，我必須得回家了。（外界的客觀原因，我不得不回家） ``` # should、ought to * 表示勸告、建議、命令 * should強調主觀看法 * ought to強調客觀要求 * 在疑問句中，通常用should代替ought to ``` You should/ought to do the job right now. Should they stay here now? ``` # need、don't have to ## need 需要 * 情態動詞 ``` He need come here early. He needn't come here early. Need he come here early? -Yes,he need./No, he needn't. ``` * 實意動詞，有第三人稱單數和時態的變化，后面可加to的不定式 ``` He needs to come here early. He doesn't need to come here early. Does he need to come here early? -Yes,he does./No,he dosen't. ``` ## don't have to 不需要，不必 回答must和have to的提問句時，否定式使用needn't/don't have to等回答方式 ``` Must I come here early tomorrow? -No,you needn't/don't have to. ``` # had better、would rather * had better 表示“最好做某事”，had雖然是過去式，但不表征過去式，better后面接動詞原形 ``` He had better eat more. You'd better finish it right now. ``` * would rather表示“寧愿、寧可、最好、還是······為好”，語感上比`had better`要輕 ``` You would rather deal with it now. ``` * 否定形式分別是： * had better not + 動詞原形 * would rather not + 動詞原形 ``` He had better not eat more. You would rather not deal with it now. ``` # used to + v、would + v 均表示過去習慣性的動作，可翻譯為：”過去常常···“ * used to 可指過去的狀態或情況，would則不能 ``` The novel used to be popular.那個小說過去很流行。 ``` * would表示反復發生的動作。如果某一動作沒有反復性，就不能用would，只能用`used to` ``` He would practise English every week.他過去每周都練習英語。 I used to live in Beijing.我過去住在北京。 ``` * used to表示過去經常性或習慣性的動作或狀態現在已經結束，would則表示有可能再發生 ``` People used to believe that the earth was flat.人們過去認為地球是平的。 He would go to the park as soon as he was free.他只要一有時間就常常去公園。 ```