Questions & Answers about Kun törmään sinuun, oletko vain lukevinasi?
How is the word lukevinasi built to mean "pretending to read"?
It uses the quasi-construction (kvasirakenne), which pairs the verb olla (here, olet) with a special form of the main verb. You take the present active participle of lukea (lukeva), put it into the plural illative form (lukevina-), and attach the possessive suffix that matches the subject (here, -si for "you").
If I wanted to ask "Am I just pretending to read?", how would this change?
Both the olla verb and the possessive suffix must change to match the new subject. The phrase would become Olenko vain lukevinani? using olen and the first-person possessive suffix -ni.
Why is the question particle -ko attached to olet and not lukevinasi?
In the quasi-construction, the olla verb acts as the primary conjugated verb of the sentence. Since yes/no questions in Finnish attach -ko or -kö to the main verb, it goes on olet to make oletko.
Why does sinä become sinuun (illative case) in the first clause?