1、情态动词 + have done sth

　　这个结构有着特殊意义：用来表示猜测（设想可能发生过什么事情）或

　　想象（设想可能出现过什么不同的情况）

　　①should (ought to) have done sth 本来该做而未做

　　This wall oughtnt to have been painted blue.

　　②need have done sth 本来有必要做而未做

　　You neednt have told her the news.

　?、踡ust have done sth 对过去所做动作的肯定推测

　　---We went to Paris.

　　---That must have been nice.

　?、躢an have done sth 对过去所做动作的否定或疑问推测

　　I dont think he can have heard you. Call again.

　　Where can John have put the matches?

　?、輒ay (might) have done sth 过去可能发生某事，与could相比，may和 might可能性较小，might 可能性更??；might 也可表示过去可能发生而未发生的事情。

　　Pollys very late----she may (might) have missed her etrain.

　　You were stupid to try climbing there. You might have killed youself

　?、辌ould have done sth

　　推测过去可能发生某事 （同can, 但can不用肯定句）

　　She could have gone off with some friends.

　　表示过去没有实现的可能性：某事可能发生，但却没有发生

　　You were stupid to go skiing there----you could have broken your leg.

　　表示有能力做而未做（虚拟语气）

　　You could have helped me !

　　(You were able to help me, but you didnt.)

　　2、can could be able to 表示能力

　　can 通常表示现在的或一般的能力---即你无论什么时候想做就能

　　做到的能力, 指单纯的表示一个人有某种能力。

　　You can certainly cook, even if you cant do anything else.

　　be able to表示某人通过努力、克服困难做成某事。

　　will be able to 表示将来的能力

　　Ill be able to speak German in another few months.

　　could 表达 一般的能力---即你过去想干什么就可以干什么

　　She could sing like an angel when she was a kid.

　　但could 不能表达过去某种具体的能力，此时用was able to, managed to 或 succeeded in 等

　　How many eggs were you able to get ?

　　3、can, could, may和might 表示可能性

　　可用来表示：①理论上的可能性（不涉及是否真发生）；②提出建议

　?。ㄌ岢鼋饩瞿掣鑫侍獾目赡馨旆ɑ蛘卟扇〉男卸虎墼谖示浠蚍穸ň渲斜泶锵衷诘目赡苄裕?/p>

　　Anybody who wants to can become a prison visitor.

　?、?--What shall we do ?

　　---We can try asking Lucy for help.?、?/p>

　　Who can that be at the door ? Can it be Polly?　　　?、?/p>

　　may　可用来表达：①将来的可能性；②说话时某事可能是真实的

　　We may go climbing this summer.　　　①

　　You may be right.　　　　　　　　　?、?/p>

　　could / might　可用来表示：?、偎祷笆蹦呈驴赡苁钦媸档?；②将来

　　某事有可能发生，但不表示特别可能发生。

　　You could be right, but I dont think you are.　?、佟?/p>

　　It could rain later on this evening.　　　　?、?/p>

　　4、can, could, may 和might表示允许

　?、偾肭笤市恚核嵌伎梢员硎厩肭笤市碜瞿呈?could 和 might并不是表示过去

　　Can (May, Could) I borrow your umbrella ?

　?、谠市恚旱蔽颐窃市砟橙俗瞿呈率?，我们用can和may来表达，而不能使用could和might

　　You may / can watch TV for as long as you like. (不用could, might; mustnt 有拒绝的意思）

　　---Could I use your phone?

　　---Yes, of course you can /may. (No, you cant / may not.)

5、can和could表示提议和请求

　　它们常用来提议为某人做某事或请求别人做某事，could更客气，更

　　含尊敬的成分，这种用法常见于陈述句和疑问句中

　?、偬嵋椋?/p>

　　Can I carry your bag ?

　　I could / can do the shopping for you, if youre tired.

　　②请求和命令：

　　Could / Can you help me with this letter?

　　You can / could start by cleaning the car.

　　6、情态动词will

　　①预测未来（第一人称用shall)，或发布命令

　　---Theres someone coming up the stairs.

　　---Thatll be Mary.

　　Youll start work at six oclock.

　　②自愿与意向

　　I will (不用 I shall) 表示自愿做某事，或主动提出做某事，或表达坚定的意图

　　---Can somebody help me ?

　　--- I will.

　　Ill break your neck.

　　will you常用来提出要求或下命令，或提出请求

　　Will you come this way, please?

　　Will you have some more wine ?

　　用wont表示拒绝

　　No, I wont !

　　She wont open the door.

　　7、shall

　　用于第一人称，表示征求对方的意见(说话人做某事)。

　　用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。

　　用于第二、第三人称，表示说话人给对方的命令、警告、允诺或威胁。

　　8、常用情态动词的回答

　?、?--Must we hand in our plan ?

　　---Yes, you must. (No, you neednt.)

　　②---Need I come ?

　　---Yes, you must. (No, you neednt.)

　?、?--May I smoke here ?

　　---Yes, please. (Certainly. / Yes, you may. )

　　(No, you mustnt. / may not. / Please dont.)

　?、?--Could / Can I offer you some coffee ? (提议)

　　(---Will / Would you have some coffee ?)

　　---Yes, please. / Yes, Id like some ,please. (不用Yes, you can.)

　　(No, thank you.) (不用No, you cant.)

　?、?--Could / Can / Would / Will you (please) open the door ?(请求)

　　---Yes, of course (I will). (No, Im afraid I cant.)

1、情态动词 + have done sth

　　这个结构有着特殊意义：用来表示猜测（设想可能发生过什么事情）或

　　想象（设想可能出现过什么不同的情况）

　?、賡hould (ought to) have done sth 本来该做而未做

　　This wall oughtnt to have been painted blue.

　?、趎eed have done sth 本来有必要做而未做

　　You neednt have told her the news.

　?、踡ust have done sth 对过去所做动作的肯定推测

　　---We went to Paris.

　　---That must have been nice.

　　④can have done sth 对过去所做动作的否定或疑问推测

　　I dont think he can have heard you. Call again.

　　Where can John have put the matches?

　　⑤may (might) have done sth 过去可能发生某事，与could相比，may和 might可能性较小，might 可能性更小；might 也可表示过去可能发生而未发生的事情。

　　Pollys very late----she may (might) have missed her etrain.

　　You were stupid to try climbing there. You might have killed youself

　?、辌ould have done sth

　　推测过去可能发生某事 （同can, 但can不用肯定句）

　　She could have gone off with some friends.

　　表示过去没有实现的可能性：某事可能发生，但却没有发生

　　You were stupid to go skiing there----you could have broken your leg.

　　表示有能力做而未做（虚拟语气）

　　You could have helped me !

　　(You were able to help me, but you didnt.)

　　2、can could be able to 表示能力

　　can 通常表示现在的或一般的能力---即你无论什么时候想做就能

　　做到的能力, 指单纯的表示一个人有某种能力。

　　You can certainly cook, even if you cant do anything else.

　　be able to表示某人通过努力、克服困难做成某事。

　　will be able to 表示将来的能力

　　Ill be able to speak German in another few months.

　　could 表达 一般的能力---即你过去想干什么就可以干什么

　　She could sing like an angel when she was a kid.

　　但could 不能表达过去某种具体的能力，此时用was able to, managed to 或 succeeded in 等

　　How many eggs were you able to get ?

　　3、can, could, may和might 表示可能性

　　可用来表示：①理论上的可能性（不涉及是否真发生）；②提出建议

　?。ㄌ岢鼋饩瞿掣鑫侍獾目赡馨旆ɑ蛘卟扇〉男卸?；③在问句或否定句中表达现在的可能性）

　　Anybody who wants to can become a prison visitor.

　?、?--What shall we do ?

　　---We can try asking Lucy for help.　②

　　Who can that be at the door ? Can it be Polly?　　　?、?/p>

　　may　可用来表达：①将来的可能性；②说话时某事可能是真实的

　　We may go climbing this summer.　　?、?/p>

　　You may be right.　　　　　　　　　　②

　　could / might　可用来表示：?、偎祷笆蹦呈驴赡苁钦媸档模虎诮?/p>

　　某事有可能发生，但不表示特别可能发生。

　　You could be right, but I dont think you are.　?、佟?/p>

　　It could rain later on this evening.　　　　?、?/p>

　　4、can, could, may 和might表示允许

　　①请求允许：它们都可以表示请求允许做某事,could 和 might并不是表示过去

　　Can (May, Could) I borrow your umbrella ?

　?、谠市恚旱蔽颐窃市砟橙俗瞿呈率?，我们用can和may来表达，而不能使用could和might

　　You may / can watch TV for as long as you like. (不用could, might; mustnt 有拒绝的意思）

　　---Could I use your phone?

　　---Yes, of course you can /may. (No, you cant / may not.)

5、can和could表示提议和请求

　　它们常用来提议为某人做某事或请求别人做某事，could更客气，更

　　含尊敬的成分，这种用法常见于陈述句和疑问句中

　　①提议：

　　Can I carry your bag ?

　　I could / can do the shopping for you, if youre tired.

　?、谇肭蠛兔睿?/p>

　　Could / Can you help me with this letter?

　　You can / could start by cleaning the car.

　　6、情态动词will

　　①预测未来（第一人称用shall)，或发布命令

　　---Theres someone coming up the stairs.

　　---Thatll be Mary.

　　Youll start work at six oclock.

　?、谧栽赣胍庀?/p>

　　I will (不用 I shall) 表示自愿做某事，或主动提出做某事，或表达坚定的意图

　　---Can somebody help me ?

　　--- I will.

　　Ill break your neck.

　　will you常用来提出要求或下命令，或提出请求

　　Will you come this way, please?

　　Will you have some more wine ?

　　用wont表示拒绝

　　No, I wont !

　　She wont open the door.

　　7、shall

　　用于第一人称，表示征求对方的意见(说话人做某事)。

　　用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。

　　用于第二、第三人称，表示说话人给对方的命令、警告、允诺或威胁。

　　8、常用情态动词的回答

　?、?--Must we hand in our plan ?

　　---Yes, you must. (No, you neednt.)

　?、?--Need I come ?

　　---Yes, you must. (No, you neednt.)

　?、?--May I smoke here ?

　　---Yes, please. (Certainly. / Yes, you may. )

　　(No, you mustnt. / may not. / Please dont.)

　　④---Could / Can I offer you some coffee ? (提议)

　　(---Will / Would you have some coffee ?)

　　---Yes, please. / Yes, Id like some ,please. (不用Yes, you can.)

　　(No, thank you.) (不用No, you cant.)

　?、?--Could / Can / Would / Will you (please) open the door ?(请求)

　　---Yes, of course (I will). (No, Im afraid I cant.)