初一英语语法之一般现在时

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情态动词表推测的用法很常见,在此,以时态和句式为基点对这一用法作了一个归纳。

(一)情态动词表推测的三种句式 1.在肯定句中一般用 must (一定),may(可能), might / could 也许, ( 或许) 。

(1) must/may/might know the answer to this question? He 他一定/可能/也许知道这个问题的答案。

(2)It is cold in the room. They must have turned off情态动词表推测的用法很常见,在此,以时态和句式为基点对这一用法作了一个归纳。

(一)情态动词表推测的三种句式 1.在肯定句中一般用 must (一定),may(可能),might / could(也许,或许)。

(1)He must/may/might know the answer to this question? 他一定/可能/也许知道这个问题的答案。

(2)It is cold in the room. They must have turned off the heating. 屋里很冷,他们肯定把暖气关了。

2.否定句中用 can’t / couldn’t(不可能), may not/might not(可能不)。

(1)It can’t/couldn’t be the headmaster. He has gone to America. 这不可能是校长,他去美国了。

(2)He may not/might not know the scientist. 3.疑问句中用 can/could (能……?)。

(1)Could he have finished the task? (2)Can he be at home now? 他可能把任务完成了吗? 他也许不认识那位科学家。

他现在能在家吗?注:以上三种句式中情态动词的语气按程度都是依次递减的。

Might, could 并非 may, can 的过去式,而表示语气较为委婉或可能性较小。

(二)情态动词表推测的三种时态 1.对将来情况的推测,用“情态动词 + 动词原形”。

1(1) She must / may / might / could arrive before 5.5:00 前她一定/可能/也许到。

(2)She must/may/might/could walk miles and miles among the hills without meeting anyone. 她一定/可能/也许会在山里一连走好几英里而遇不到一个人。

2.对现在或一般情况的推测,用“情态动词 + be”,“情态动词 +be doing”或“情态动 词 + 动词原形”。

(1)He must / may / might / could be listening to the radio now. 也许正在听收音机。

(2)He can’t ( couldn’t ) / may ( might ) not be at home at this time. 这个时候他不可能/可能不在家。

(3) Bush is _disibledevent="EN-US">3.对过去情况的推测, Mr. 用“情态动词 + have +过去分词”。

(1)It must / may / might / could have rained last night .The ground is wet. 地湿了,昨晚肯定/可能/也许下雨了。

(2)The door was locked. He can ( could ) not / may ( might ) not have been at home . 门锁着,他不可能/可能不在家。

(3)Can / Could he have gotten the book? 难道他找到书了吗? 他一定/可能/注:情态动词 should /ought to 表推测时,意为“想必会,理应……”但与“have +过去 分词”连用时,则又可构成虚拟语气意为“本应该做某事却没做”。

例如: (4)It’s seven o’clock. Jack should/ought to be here at any moment. 现在七点钟了,杰克理应随时到达。

(推测) (5)She should / ought to have attended your birthday party, but she had to look after her mother in hospital. (虚拟) 她本该出席你的生日晚会的,可是她得在医院 照顾她妈妈。

2(6)Tom should not /ought not to have told me your secret, but he meant no harm. (虚拟) 汤姆本不该告诉我你的秘密,可是他并无恶意。

三. 疑问句中用 can/could (能……?)。

(1)Could he have finished the task? 他可能把任务完成了吗? (2)Can he be at home now? 他现在能在家吗? 四.反意问句 若陈述句中有 must, can’t,may ,may not...等表示推测的词时,先去掉 must, can’t,may ,may not...等表示推测的词, 根据时间状语或时态定义恢复动词为适当形式,再根据情况用助系反问 1. He must be an engineer,isn’t he? 2. She must have a car,doesn’t she? 3. She can't be a teacher,is she? 对某一次的推测句型有两部分:语气和时态 语气部分:(以下情态动词语气由强至弱) 肯定句:must、may、might(=could) 否定句:can’t(=couldn’t)、mayn’t、mightn’t 疑问句:can、could(语气更加委婉不确定) 时态部分: be 表示对现在的推测3have done 表示对过去的推测 be doing 表示对正在进行的推测 语气部分写在前时态部分写在后,组合在一起就是推测 ◎—Excuse me. Is this the right way to the Summer Palace? —Sorry, I am not sure. It ________ be. (湖北卷) A. might B. will C. must D. can【分析】答案选 A。

由 I am not sure(我没有把握)可知,后文是没有把握的肯定推测,用 might。

◎You might just as well tell the manufacturer that male customers ________ not like the design of the furniture. (上海卷) A. must B. shall C. may D. need 【分析】答案选 C。

. may not 意为“可能不”。

句意是:你不妨告诉厂商男顾客可能不喜欢 这种家具的花样。

◎—Isn’t that Ann’s husband over there? —No, it ________ be him—I’m sure he doesn’t wear glasses. (全国卷) A. can’t B. must not C. won’t D. may not【分析】答案选 A。

由 No 和后文 I’m sure…可知,是有把握的否定推测,所以用 can’t (不 可能)。

◎—When can I come for the photos? I need them tomorrow afternoon. —They ________ be ready by 12:00. (全国卷) A. can B. should C. might D. need【分析】答案选 B。

should 表示“按理应当,大概”。

用 might 语气太不肯定,顾客可能走 掉。

◎I have lost _disibledevent="EN-US">)4A. must drop droppedB. must have droppedC. must be droppingD. must have been【分析】答案选 B。

对已经发生的事进行推测用“must have +过去分词”,答案 D 是被动 式,应排除。

◎—I stayed at a hotel while in New York. —Oh, did you? You ________ with Barbara. (全国卷) A. could have stayed B. could stay C. would stay D. must have stayed【分析】答案选 A。

表示对过去情况的推测:“你可能和 Barbara 住在一起了”;must 语气 太肯定,与前面具有疑问语气的 Oh, did you?不符。

◎—There were already five people in the car but they managed to take me s well. —It ________ a comfortable journey. (全国卷) A. can’t be B. shouldn’t be C. mustn’t have been D. couldn’t have been【分析】答案选 D。

既然小汽车上“已有五人”,且是“设法”才把你带去的,如此拥挤,旅 途当然“不可能”舒服。

◎—Tom graduated from college at a very young age. —Oh, he ________ have been a very smart boy then. (全国 III) A. could B. should C. might D. must【分析】答案选 D。

由上文可知,应是有把握的肯定推测,用 must(一定)。

◎You ________ be tired—you’ve _disibledevent="EN-US">) A. must not B. won’t C. can’t D. may not【分析】答案选 C。

由后文“你才只工作了一个小时”推断,“你不可能就累了”。