Didn't or Haven't (I didn't write a letter for the last six months.)

[Ganesh]

Dear Teacher

I didn't get the answer for the following yet please.

Please let me know whether the first sentence or the second sentence is correct:

I didn't write a letter for the last six months.
or
I haven't written a letter for the last six months.

Ganesh

[Alan]

Hi Ganesh,

You should use the present perfect tense as in: I haven't written a letter for the last six months.

I didn't write a letter (past simple) would have to refer to a particular time in the past as in: I didn't write a letter last night.

Alan
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English as a Second Language
You can read my ESL story Present Simple

[Ganesh]

Hi Alan

Than you very much for your very useful and very good explanation
Many thanks

Ganesh