Learn Turkish: Uzaylılar piramitleri inşa etmiş olamaz. - Aliens cannot have built the pyramids.

This is the negative epistemic past deduction taught in this lesson. It combines the past participle suffix -miş on the main verb (etmiş) with the negative potential form of the auxiliary verb olmak (olamaz). It literally means "it cannot be that they built," expressing a strong deduction that something didn't happen in the past.

Why is the verb etmek used here instead of adding suffixes directly to inşa?

inşa is an Arabic loanword meaning "construction", not a verb itself. To make it a verb, Turkish uses the helper verb etmek (to do/make). The grammar structure -miş olamaz must attach to the helper verb, creating inşa etmiş olamaz.

Why doesn't the 't' in piramit mutate to a 'd' when adding the suffixes for piramitleri?

We are talking about specific objects ("the pyramids"), so it needs the definite accusative suffix -i after the plural -ler. While Turkish usually changes a hard 't' to a 'd' before a vowel, piramit is a foreign loanword and is an exception to the consonant mutation rule, so it keeps the 't'.

How does the suffix -lı work in the word uzaylılar?