Learn Hardcore Korean: amachueo geukdaneun hwayoire yeonseupsireseo mannasseo. - The amateur theatre company met in the rehearsal room on Tuesday.

Breakdown of amachueo geukdaneun hwayoire yeonseupsireseo mannasseo.

Why does 극단 take -은 in 아마추어 극단은?

-은/는 is the topic marker. It marks 아마추어 극단 as the thing the sentence is about.

So 아마추어 극단은 means something like:

In this sentence, it sets up the group as the topic, and then the rest of the sentence tells you what happened to that topic.

A learner might compare it to -이/가, which is a subject marker. Very roughly:

Both can be possible in some contexts, but -은 here sounds natural if you are talking about that group and giving information about what it did.

Why is 화요일 followed by -에?

-에 is often used with time expressions to mean at/on/in.

So:

This particle is very common with days, dates, and clock times.

Examples:

Also, in everyday Korean, -에 is sometimes omitted with certain time words, but with 화요일, keeping -에 is completely standard and clear.

Why is it 연습실에서 and not 연습실에?