Where do we use "could"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hi,

could you please give me a note?

can you please give me a note?

Is there any major difference ?

Thanks
geetha

2

Hi Geetha

In your sentences, using “could” makes the request a little more polite.
Using “can” would basically be a more informal request.
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3

hi,
thanks lot.for a long time i have this doubt.it is cleared now

4

in the past tense, don’t use “can” but use “could” or “was able to”.

5

Another use:
I could not modify the file.

In other words: (In the past) I was unable to modify the file.
Could should be used for : See,understand, smell,hear (senses).

But, some people use could and able interchangebly, i think.
Maybe it is not a mistake in terms of grammer.

6

Yes, that’s true, Johnnywill. However, in Geetha’s sentence, the word “could” is not used as a past tense. Because Geetha’s sentence also contains the word “please”, the word “could” is used in order to make a request more polite.
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