Translation:My parents have shown me a map of Poland.
"Have shown" is present perfect. This category is called Past Perfect, so it must be "had shown."
use whichever tense you want, as long as it means they finished showing it, and you have seen it.
Understood. I'll stop commenting on it. I'm sure my reports have been seen. Maybe the developers will change the name of the category. This should be Past Perfective Aspect, which English doesn't have. Simple past tense in English implies the "completed" task of past perfective in Russian (apparently Polish too).