情态动词_121478.ppt

?一、情态动词的特点:? 。? 2. 有些情态动词有过去式的变化: ? . will → would , can → could , may → might , dare → dared ?二、情态动词的否定式: ?情态动词+ not + 动词原形 can not: can't , must not: mustn't , need not : needn't 三、情态动词的用法及相互区别三、情态动词的用法及相互区别, , 是考试的内容之一。是考试的内容之一。 1. can , be able to 1. can , be able to be able to be able to 表示经过努力后表示经过努力后, , 能够能够做到做到; be able to ; be able to 有多种形式的变化。有多种形式的变化。 can can 1). 1). 表示体力或脑力方面的能力表示体力或脑力方面的能力; ; 2). 2). 表示允许、可能性。表示允许、可能性。 could could 是是 can can 的过去式的过去式, , 表示过去有能力及过去存在的可表示过去有能力及过去存在的可能性能性 ; ; 用于疑问句表示委婉地提出问题。用于疑问句表示委婉地提出问题。 1) The fire spread through the hotel very quickly but 1) The fire spread through the hotel very quickly but everyone ____ get out. everyone ____ get out. (NMET 97 ) (NMET 97 ) A. had to A. had to B. would B. would C. could C. could D. was able to D. was able to 2) -Will you stay for lunch? 2) -Will you stay for lunch? -Sorry, __. My brother ing to see me. (NMET99) -Sorry, __. My brother ing to see me. (NMET99) A. I mustn't A. I mustn't B. I can't B. I can't C. I needn't C. I needn't D. I won't D. I won't 表示询问或说明一件事可不可做; 表示某事有可能发生。 might 是 may 的过去式; 用在疑问中比 may 委婉、客气。 1) -May I take this book out of the reading-room? -No, you mustn't. ( Yes, you may.) 2) -Might I make a suggestion? - Yes, you may. 3. must 1). 表示必须要做的事: 必须 2) 表示很有把握的推断: 一定, 准是。 have (has)to : have (has)got to 必须, 不得不。过去式: had to 3) -Must I get to the station before three o'clock? -Yes, you must. ( No, you needn't. ) 4) I'm afraid you will have to wait a while. 5) She must be in the classroom now. 6) Mary ____ be in Paris, I saw her in town only a few minutes ago. (NMET 94) A. mustn't B. shouldn't C. can't D. may not (1) must 表示“必要”“必须”时,附加部分用 mustn ’t…?或者说 needn ’t…? (2) must 用于否定形式 mustn ’t时,附加问句部分用 may 或 must 。(3) must 表示“推测”意义时,要根据具体情况而确定。例如: He must know the secret, doesn ’ t he? 他一定知道这个秘密,不是吗? He must be a teacher, isn ’ t he? 他一定是个老师,不是吗? You must have seen him off yesterday, didn ’ t you? 你昨天一