I cannot understand well why we add ''le'' and ''lor'' in the sentence. Are both of them essential or we emphasize more by their usage?
(Noi) le-am arătat (lor) casa noastră works. Noi and lor are not necessary.
Thank you very much for your answer! it's exactly as we say in Greek (my native language).
You would only use noi le avem (without the dash like symbol) to mean we have them.
The usage of the a avea verb in le-am is because that's how some verbs like a arăta can be used in this tense.
This is how the Past Tense is formed. Example: i listen to- eu ascult in Present Tense and i listened-am ascultat. ''Le avem'' would mean ''we have them'' but in this sentence we want to say ''we showed to them our new home'' which is an action that refers to past, so we need to use the past test form of the verb ''a arata''.
This is called the Compound Perfect Indicative tense, and to form it you use the following structure: (eu) am/ (tu) ai / (el/ea) a / (noi) am / (voi) ați / (ei/ele) au + past participle. For example, the past participle of "a lucra" is lucrat, so you can say "(el/ea) a lucrat" = he/she worked, "noi am lucrat" = we worked, etc.
Hope this helps! :)