[Grammar in Use, intermediate] Unit 25. Can, could, and (be) able to

##### Unit 25. Can, could, and (be) able to 

~ 할수있다.

#1. Can

a. We use "can" to say that something is possible or allowed, or that somebody has the ability to do something. 

* We use can + base form (can do / can see, etc.):

+ We can see the ocean from our hotel window.

+ Can you speak any foreign languages?

+ I can come and help you tomorrow if you want.

+ The word "dream" can be a noun or a verb.

* The negative is can't(= cannot)

+ I'm afraid I can't come to your party on Friday.

#2. is able to

a. You can say that somebody is able to do something, but can is more common:

+ We are able to see the ocean from our hotel window.

b. Can has only two forms: can (present) and could (past). 

So sometimes it is necessary to use (be) able to. 

I can't sleep.	I haven't been able to sleep recently.
Tom can come tomorrow.	Tom might be able to come tomorrow.
Maria can speak French, Spanish, and English.	Applicants for the job must be able to speak two foreign languages.

#3. Could

a.  the past of can (use it especially with : see / hear / smell / taste / feel / remember / understand)

+ We had a nice room in the hotel. We could see the ocean.

+ She spoke in a very soft voice, so I couldn't understand what she said.

b. use it to say that somebody had the general ability or permission to do something:

+ My grandfather could speak five languages.

+ We were totally free. We could do what we wanted.

#4. Could & was able to

positive		negative
could	use it for general ability	couldn't
was able to	use it somebody did something in a specific situation
managed to

compare:

+ Jack was an excellent tennis player when he was younger. He could beat anybody. 

+ Jack and Ted played tennis yesterday. Ted played very well, but Jack managed to / was able to beat him.

# Exercises

+ We had a really good vacation. It couldn't have been better.

+ I couldn't have wear that hat. I'd look sill, and people would laugh at me.

+ We managed to find the restaurant you recommended, but we couldn't have find it without the map that you drew for us.

+ The staff at the hotel was really nice when we stayed there last summer, They couldn't have been more helpful.

+ That's nice of you, but I couldn't have come anyway. I was away all last week.