Hi,

use: I was able to swim across the river.(you did it some time ago)

If you say : I could swim across the river, you haven't done it. You just claim that you would be able to swim across the river. And I think you want to express that you did the procedure in the past. That's why you have to use the simple past.

But if you want to make a claim, the use "cou

"I managed to swim across the river" is talking about a specific past occasion when you succeeded in swimming across the river.

"I could swim across the river" is talking about your past ability to swim across the river. It's a relatively unusual thing to say as a standalone sentence. Usually there would be some other words involved, such as "When I was young I could swim across the rive

Thank you for your answers.Could you also help me with one more question?
We finished our work early and so we were able/managed to catch the train.
If I say:We finished our work early and so we could catch the train.,is it gramatically correct?
Does the meaning change?
Thank you again

Mr Wordy"I could swim across the river" is talking about your past ability to swim across the river.

Actually, I overlooked the fact that this wording might also be used to describe present ability to swim across the river. In this sense it has a similar meaning to "I can swim across the river", but with an unstated hinted or implied conditional: "

Anonymous
We finished our work early and so we were able/managed to catch the train.

If I say:We finished our work early and so we could catch the train.,is it gramatically correct?

Does the meaning change

"We finished our work early and so we could catch the train." -- doesn't seem right.

"We fini

AnonymousIs it correct if I say: I could swim across the river.,or it must be:
I was able/managed to swim across the river?

If you want to indicate a successful attempt to swim across the river, you must use one of these:

I was able to swim across the river.
I managed to swim across the river.

AnonymousWe finished our work early and so we were able/managed to catch the train.
If I say:We finished our work early and so we could catch the train.,is it gramatically correct?

This is exactly the same as the previous example. If you wish to indicate a successful attempt to catch the train, you need:

... we were able to catch the tra

CalifJimcould is never appropriate for communicating that a successful attempt has been made.

Maybe I'm not quite understanding your point, but if someone said, per the example given, "We finished our work early so we could catch the train" then I would normally assume that they had successfully caught the train.

As mentioned, COULD can't be used for a particular past instance. In modern English, is the following natural English? (it sounds not to me, but I can't think of a way to improve it.

-But when, on the outskirts of Paris, Miss Burshaw had counted heads, it was discovered that only eighteen girls could be found!