高中英语新高考语法二轮复习讲义（17）助动词（would、can、could、may、might、must）用法知识点总结整理

高中英语新高考语法一轮复习讲义（17）助动词（would、can、could、may、might、must）用法知识点总结整理——wouldwould是will的过去式，用来表示过去将来时例：He said that he would try again.（他说了他会再试一试）Did you know when he would come?（你当时知道他何时会来吗）有时也会出现will与一般过去时连用的现象
 例：He said that he will visit the country sometime in July（他说他会在七月份访问该国）那么怎么区分使用will还是would呢？He said虽然为过去状态，但will是用于尚未到来的时间，而would用于已经过去的时间。例：He said that he will visit you tomorrow（他说了他明天会来拜访你）He said that he would visit you yesterday（他说了昨天会来拜访你）would用在虚拟语气中，表与现在或过去事实相反
 与现在事实相反：would + 动词原形     译为“就会……”例：If I had money now, I would buy a big house.（如果我有现在有钱，我会买一套大房子）与过去事实相反：would have + 过去分词例：If we had left earlier, we would have been able to stop off for a coffee on the way.（如果我们出发早一点，我们就能在去的路上停下来喝一杯咖啡）用would表示过去特别的习惯或者动作例：I had a friend from Albany, which is about 36 miles away, and we would meet every Thursday morning and she would help us.（我有一个来自奥尔巴尼的朋友，大概有36英里远，我们经常在星期三早上见面，并且她经常帮助我们）用would表示间接委婉建议，经常和advise, imagine, recommend, say, suggest等词连用在请求或寻求帮助时，用would代替will以表礼貌正式would常用的一些搭配would rather + 动词原形     宁愿……例：I would rather go than stay here（我宁愿走也不愿意呆在这里）would you mind + v-ing  你介不介意……？例：Would you mind using your book?（你介不介意用一下你的书？）would rather +（that）从句   我多么希望……此句型属于虚拟语气，若与现在事实相反，that从句用一般过去时；若与过去事实相反，用过去完成时态。与现在事实相反：I would rather（that）he were here.（我多么希望他在这里）与过去事实相反：I would rather（that）he had been here yesterday（我多么希望他昨天在这里）——can 和could助动词can有下列意思和用法①  表做某件事的能力，翻译为“能够”例：I can sing one song in Polish（我能用波兰语唱歌） 常与感官动词hear, see, smell, taste, 思想类动词 guess, imagine, picture, understand  follow等连用例：I can hear you.（我能听到你）I can guess why you’re angry.（我能猜到你为什么生气）② 表可能性，翻译为有可能We can go to Rome in June because both of us have a week off work.（我们能去罗马，因为我们都有一周的休息时间）在疑问句中：can it be true？（这可能是真的吗）③ 表许可，译为“可以”Can I take Daisy for a walk?（我可以和黛西散步吗）Students can use calculators during the exam.（学生在考试时可以用计算器）④ 表对过去事实的否定推论can't have + 过去分词   不可能曾……He is so busy that he can't have stolen you money yesterday.（他很忙昨天不可能偷你的钱）注意：can不可用于对过去事实的肯定推论，要表对过去事实的肯定推论可用以下两种句型：must have + 过去分词      一定曾经……may have + 过去分词        可能曾经……
 例：He looks nervous，he must have stolen you money.（他这么紧张，一定滴偷了你的钱）could为can的过去式，通常用以表示过去的状况
 例：She could speak English well when she was ten.（她10岁时英语就说得很好了）In those days, you could buy everything in the local shop. Now we have to go to the big supermarket for everything.（哪些天你们能在当地超市买想要的东西，现在我们不得不去大超市买了）could = was/were able to 表示过去的能力，用于一般过去时中
 例：He was able to eat eight bowels of rice when he was young.（他年轻时能吃8碗米饭）Could使用于问句中表示客气Could you please do it for me ?（你能帮我做这事吗？）Could have + 过去分词 用来表示本应该发生而为发生的事情，表遗憾He could have been a doctor.（他本应该成为一名医生的）I could have been famous.（我本应该很出名的）有时也会用how could you/she/he/they……？来反对某事例：How could you have gone without telling me?（你怎么能不告诉我一声就走了呢）Grandfather,How could you leave me?（爷爷，你怎么能够抛弃下我呢）can与not连用时，不要写成can not，而要写成cannot或者can't例：He cannot write letters（他不会写信）can的惯用语can but/only    只能……I can but/only do so.（我只能这么做）cannot help doing    禁不住……例：I cannot help laughing.（我忍不住大笑起来）——may和might助动词may之后接原形动词，有以下意思及用法表许可译为“可以”，询问显得有礼貌
 例：You may take whatever you like.（你喜欢什么就拿什么）May I borrow the car tomorrow?（我明天可以借这辆车吗）表推测,译为“可能”，此时等于canJack may be coming to see us tomorrow.（杰克明天可能来看我们）表祝愿：may you be happy in the future（祝你余生快乐）否定形式为may not，同样有表许可和推测的意思，分别译为“可能不会”和“不可以”might通常与一般过去时连用，表过去的状况有关may的惯用语May well +原形动词 大可/足可.....He knows so many things that he may well be called a genius他懂得那么多，大可称得上天才May as well +动词原形 不妨.... You may as well stay at home (你不妨待在家里)You had better stay at home (你最好待在家里)语气较强May as well+动词原形+as+动词原形 与其....倒不如.... You may as well stay home as go out with them你与其和他们出去，倒不如待在家里——must   must之后接原形动词① 表义务译为“必须”You must finish your task before leaving（你一定要在离开前完成你的任务）
 ② must可表对现在状况或过去的推论现在的推论：must + 原形动词      一定……He’s so small，he must be no more than four years old（他这么小，一定不会超过四岁）过去的推论：must have + 过去分词    一定曾经……I called you yesterday around three o’clock but you must have been out.（我昨天大约三点打过电话给你，你一定是出去了）③ 否定形式：must not  不可以You must not leave any rubbish.（你不可以乱扔垃圾）④ must与have to 的比较must表示义务强制的必须，侧重于说话者的主观看法；而have to 有勉强、被迫的意味，侧重于客观需要。 另外，must只用于表现在或将来的状况，而have to可用于表过去、现在、将来的任何状况。