A general or a specific ability

[henz988]

Yesterday, I could lift the couch by myself. Not Correct
http://www.englishpage.com/modals/could.html

1. I could do it yesterday.
2. I could raise the desk yesterday.

My question is,
Are 1&2 not correct? or on what occasions could they be correct?


Many thanks.

[Barb_D]

I will be interested to hear from others. I see no problem with the original "incorrect" sentence from a grammar point of view.

[~Mav~]

You might be interested in this thread, where the interchangeability (or lack of it) of "could" and "was/were able to" has partly been covered.

[Gillnetter]

I will be interested to hear from others. I see no problem with the original "incorrect" sentence from a grammar point of view.

From the source- "Could" cannot be used in positive sentences in which you describe a momentary or one-time ability.
Yesterday, I could lift the couch by myself. Not Correct

That's silly. Maybe this is an American thing but that rule doesn't make any sense to me. Consider - Yesterday, because of a mirror being placed behind the moon, a one time event that only lasted for only two seconds, I could see the back side of the moon.

[henz988]

I could see the back side of the moon.

Thank you, Gillnetter.
This seems to be a little off from the “could” I am going to learn because “could” can be used with “feel, hear, see, smell, taste” as well as “thinking, believe, decide, remember” to mean a one-time ability. This usage is not confusing for an ESL.

Thanks also go to Mav for the link. However, the thread has "deepened" my confusion instead of clarifying anything. And that’s one of the readings that makes me the starter here.
---------------
1. I could lift the couch by myself yesterday, but I didn’t. If I am asked, I can flex my muscles here.
2. I could lift the couch by myself yesterday, and I was praised by my girlfriend then.
I have no problem with sentence1.
I don’t know whether sentence2 is correct, at least it is grammatical. However, I would use “was able to” rather than “could”. I feel in this case, “was able to” gives an implicitly of surprise.

What do you think of sentence2 both in grammar and in its meaning? If it is wrong, could you please explain why, other than "one-time ability"?


Thank you again.

[bhaisahab]

I will be interested to hear from others. I see no problem with the original "incorrect" sentence from a grammar point of view.

I agree, there's nothing wrong with it that I can see.

[5jj]

I thimk that if the the line had been: "Could" is not normally used in positive sentences in which you describe a momentary or one-time ability, it would have been closer to the truth.

'Rules' containing such words as 'normally', 'generally', etc, are frustrating, but modals are notoriously difficult to pin down precisely.

My own feeling is that we are more likely to use 'BE able to', 'managed to' or some other verb (phrase) than 'could' in affirmative sentences about a activities we actually carried out in the past.