"Moi rodzice pokazali mi mapę Polski."

Translation: My parents showed me a map of Poland.

[IlliaSokolovskyi]

my parents have showed me a map of Poland
is it incorrect?

[Jellei]

It's rather rare (using 'have showed' instead of 'have shown'), but we decided to accept it. Added.

[johnsuther5]

I would say that this is a bit clunky. You would usually say "I have shown/seen/run/given/eaten/ written etc" or "I showed/saw/ran/gave/ate/wrote". However there are other verbs that could be used interchangeably with or without "have", for example "I have heard/said" or "I heard/said" are equally good constructions used according to the context.

The use depends on context. I would generally use "have shown" where this refers to an action at some unspecified time in the past. If it was to emphasise when the action occurred I would use "I showed (this to you yesterday)".

[Jellei]

I can agree that "showed" seems more likely here and it's definitely a good translation of the Polish sentence. Changed now.

[chce_polski]

Jaka wersja?