Hello. "Can" and "able to" both mean the ability to to something and you can sometimes choose which one you want to use (but not for all situations where it isn't grammatically correct) For instance: can put help me? Means are you able to help me. If you are making a request: Will you help me? If you are a statement, you would say: He wasn't able to help me. (In this case, you don't use the word can) You are allowed to use can in past tense: He couldn't help me.

If the water is not frozen then I will can swim. If you find your glasses then you will can read it. If you pay the bus ticket, then she will can go there. If he stops the bleeding, then he will can survive. ...... we would say if English were logical. It is not logical. We say instead: If the water is not frozen then I will be able to swim. If you find your glasses then you will be able to read it. If you pay then she will be able to go there. If the bleeding stops, then he will be able to survive. So: we will can run (good logic, bad grammar) = we will be able to run (bad logic, good grammar). In short: ''will can + verb-infinitive'' = ''will be able to + verb-infinitive''. ---------------------- It gets worse. And this ''will be able to'' begins to meddle with the present tense. ------------------ Instead of saying 1.''I can speak English'', you often hear 2.''I am able to speak English''. Why say 2 when you can say 1? In my opinion, ''was/were/am/are/is able to'', wherever you find them, should be instantly replaced with ''could/can''.

Thanks guys!

A slight difference in meaning is "can" suggests something more to do with permission and "able" suggests something to do with ability. If a teenager's parents say "she can drive the car" then that suggests that she has a driver's license and their permission to drive the car. If they say "she is able to drive the car" that suggests that she may have the ability to use the gas peddle and brake and clutch correctly, but it doesn't mean she should do it. I also think that saying "able" emphasizes the activity more strongly than "can." If somebody asks me "Can you walk to the grocery store?" they're probably just asking if I have the time to do it, and would I be willing to. If they say "Are you ABLE to walk to the grocery store" they are probably asking if I'm physically capable of walking there. In most instances, they can be used interchangeably without causing any confusion, but sometimes one may lend a slight difference of emphasis.

They are almost completely the same. The only differences I can think of are these: You only use "able to" for an ability you will only have in the future. Ex. "I will be able to speak fluently after I complete the course." You cannot say "I can speak fluently after I complete the course." You only use "able to" when talking about a specific past action. Ex. "I was able to read the whole chapter yesterday." You cannot say "I could read the whole chapter yesterday." Those are the only two differences I could think of. Hope this helps. :)