专题03 情态动词和虚拟语气-【口袋书】2023年高考英语必背知识手册（思维导图+背诵手册）（全国通用版）

专题03 情态动词和虚拟语态 情态动词 ★ 情态动词：can, could, may, might, must, ought to, shall, will, would, need ,dare 1. 表示推测的情态动词 1.1基本原则： 1.1.2 对现在或将来情况推测，用情态动词+do / be / be doing… 对过去的推测，用情态动词+have done / been… 1.1.3表示肯定推测的情态动词,按可能性由大到小依次为:must> should / ought to>may>might>could 1.1.4否定推测，按语气由强到弱依次为： can’t / couldn’t（根本不可能）>may not> might not/could not(可能不)。 1.2 具体用法： 1.2.1 must be表示推测，意为“一定是……” 只用于肯定句中 must have done意为“一定做过某事或某事肯定发生了” 并且有前文铺垫 e.g. Listen! There must be some children in the room. The road is wet. It must have rained last night. 1.2.2 should (not) / ought (not) to在中表示根据常规或常识推测，表示“某事应该或不应该发生” e.g. It is nearly 7 o’clock. Jack should be here at any moment. You shouldn’t be texting in the class now. We are having a lesson. (should not 含有责备之意) 1.2.3 can, could表达推测时，一般用于疑问句和否定句中；can用于肯定句中表示一种理论上的可能性，意为“有时候会…”，并不牵涉是否真的会发生；could用于肯定句中，语气比may/ might更弱。 e.g. It is usually warm in my hometown in March, but it can be rather cold sometime. 1.2.4 may (not) / might (not)表达一种不太把握的推测，意为“或许，可能”；might的语气比may较婉转。 e.g. Although this may sound like a simple task, great care is needed. 2. 表达虚拟语气的情态动词 2.1 适用情况：对过去的一种结果的假设或虚拟，形式：情态动词+have done 2.2 具体用法： 2.2.1 should (not) / ought (not) to have done本（不）应该做某事，但却没有做或做了，含有责备或后悔之意。 e.g. You should have gone over your lesson yesterday. (In fact, you didn’t go over your lesson yesterday.) 2.2.2 could have done本来能够做某事但未做。 e.g. If you followed my advice, you could have finished it. 比较一下这一句： The road isn’t wet. It couldn’t/ can’t have rained last night. (对过去的猜测) 2.2.3 needn’t have done: 本没有必要做某事但却做了。 needn’t do: 没有必要去做某事 (时间上应该是现在或将来)。 e.g. —Catherine, I have cleaned the room for you. —Thanks. You needn’t have done it. I could manage it myself. You needn’t do it. I’ll do it later. 2.2.4 would (not) have done:本来(不)会发生某事，但却（发生了）或没有发生。常用于虚拟条件句或含蓄虚拟条件引导的虚拟语气，表示对过去所发生事情结果的假设。 e.g. He hesitated for a moment before kicking the ball, otherwise, he would have