could/would have written

[Saneta]

Don't be angry with Susan. She doesn't have your address. Otherwise she could have written to you much earlier.

Could I say: would have written instead of: could have written? what is the diffirence between them and when should we use each of these two expressions?

Thank you very, very much.

Saneta

[Esl_Expert]

Hi Saneta,

First of all, it would make more sense to use 'didn't' rather than 'doesn't' in the second sentence. The words 'much earlier' suggest that she has now written and thus that she also has the address now.

That said, yes, you can replace 'could' with 'would'. The difference is that 'could' refers to past ability, but 'would' does not. In the context, I would describe the use of 'would' as a past prediction (of the future).

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"If we knew what it was we were doing, it would not be called research, would it?" ~ Albert Einstein

[Beeesneees]

You could use that alternative.

would have - indicates that it is something she definitely intended doing.
could have - indicates it is something she possibly intended doing.
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Cheers m' dears!

[Saneta]

Thanks a lot to both of you :)
the little question to Esl Expert:
The words 'much earlier' suggest that she has now written...- is word: now can between: has and written, or it should be:
The words 'much earlier' suggest that she has written now...
thank you again...