'can' in the past tense - why not?
 

I've got some students here who have a problem with L1 transfer. In Japanese, my students would say 'I went to a conference last week and *I could make some friends.'

I need to make a lesson plan that shows them when they should just use the plain past and when to use 'was/were able to ~', but first I need to understand why we don't say *'I could make some friends.'

Is it just that it's confusing with the subjunctive?
- If I went, I could make some new friends, but I have other plans.'

Is that just the way it is?

Re: 'can' in the past tense - why not?
 

Hi Mark;
Long time! Finally back after months of sleepless nights (and sadly i'm not exaggerating). In fact, let's use sleepless nights and newborn babies as an example :-)

When using the past of can ie could, we can only use it in positive sentences when it refers to a general situation, rather than a specific one-off.
Here are two specific situations:
Last night I was able to make my son sleep :-) - correct.
Last night I could make my son sleep :-) - incorrect, because it's a specific situation.

Here are two general situations:
When I lived in London I was able to get around very easily - correct.
When I lived in London I could get around very easily - correct.

For negative sentences, you can use be able to or could for both specific and general situations:
Last night I wasn't able to sleep because my son has a cold - correct.
Last night I couldn't sleep because my son has a cold - correct.

When I was a child I wasn't able to swim - correct.
When I was a child I couldn't swim - correct.

I hope that helps.
Speak soon
Clive

Re: 'can' in the past tense - why not?
 

Hi!
I've found some examples that show the difference between could and was able to.

- We use could have to say we were able to do sth, but in fact we didn't.
He could have helped me, if he'd tried. (= but he didn't)

- For general ability in the past we also use was able to, though could is more common.
I could/was able to swim when I was five years old.

- For a specific event showing success after trying, we use was able to, managed to, or succeeded in, but not could.
I was able to/managed to solve her problems for her.

- We use couldn't have to say we were not able to do sth so we didn't.
He couldn't have helped me anyway. (= he didn't)

I hope this will help you. Good luck! :)

Re: 'can' in the past tense - why not?
 

Clive and ordeal, thanks. That ought to get me rolling.

And Clive, welcome back!

Re: 'can' in the past tense - why not?
 

Thanks Mark - it seems like years. It's nice to be back. Heaven knows I'm in need of some fresh input !! All well in Japan with family and work?

Re: 'can' in the past tense - why not?
 

All's better than great! Only thing that would make it better is more time to enjoy it. :D

Kids and wife are good, and I'm still busier than I want to be. Not much has changed ...

Looking at those pictures makes me think I need to go visit you for a few weeks and another TEFL certificate :)