Could – different usages.

(1)  ‘ Could ‘ refers to the past ability/ perception.(general or particular)

• My grandfather could speak five languages.(general)
• When we went into the house, we could smell something burning.(particular)
• I could not grasp what the old man said.(particular)

(2)  We use ‘ Could ‘ for general ability.  But, if we are talking about what happened in a particular situation, we use  ‘was/ were able to ‘.  When we use ‘ Managed to….’ , it has a special connotation that a certain amount of difficulty was involved in doing the action.

• We were able to persuade him to come for the function.(refers to a particular situation)
• Running fast, I was able to catch the bus.(refers to a particular situation)
• There was heavy rush for the show but I managed to secure a seat.(refers to a particular situation involving difficulty)

(3)  ‘ Could ‘ serves a purpose similar to that of ‘ Can ‘ , but more hesitant, less direct than ‘ Can, May, or Might ‘.

• Could this be the right answer?
• This could be the answer.  What do you think?

(4)  The negative ‘couldn’t ‘ ( could not) is possible in all situations.( i.e specific or general situations)

• I could not swim when I was a boy.
• We tried hard but we couldn’t persuade him to accept our proposal.

(5)  We also use ‘ Could ‘ to talk about possible actions for ‘Now ‘ or for a ‘ Future time’.  ‘Can’ is also possible in the place of ‘ Could ‘ ( especially to make a suggestion)

• What shall we do this evening ?
• We could go to the cinema.
• It’s a nice day.  We could go for a walk.
• (OR) We can go for a walk.
• When you go to Mumbai next month, you could stay with my uncle.  It will not be a problem for him.  He has his own flat there.

(6)  You must use ‘ Could ‘  ( Not can) when you don’t really mean what you say.

• I am so angry with him.  I could kill him.(  we do not say, ‘I can kill him’.This usage shows the intense state of anger Or it involves a little bit of exaggeration)
• I could smack his face! (here one does not smack another)
• I am so hungry.  I could eat a horse.( actually one does not eat a horse)
• I am so tired.  I could sleep for a week.( one does not ,actually, sleep for a week)

(7)  We also use ‘ Could ‘ to say that something is possible now or in the future.

• The phone is ringing.  It could be my sister Soja.
• They could arrive at any time.  Please finish all the preparations soon.

(8)  ‘ Could ‘ refers to possible freedom from other engagements.

• I could see you tomorrow at 10 a.m perhaps. ( which is less definite than ‘ I can see…)

(9)  ‘ Could ‘ for grants, permissions etc.

• Could I borrow your pen , please?
• Yes of course you could.
• (OR) I am afraid you couldn’t. ( if the answer is in the ‘Negative’)