Yes. This is αυτός ο for masculine nouns, αυτή η for feminine nouns and αυτό το for neutrum nouns.

Tru

You really hear a "b" sound in it: https://www.duolingo.com/dictionary/Greek/%CF%84%CF%81%CF%89%CF%82/bbad7442ede86d7268f993eb22c8b212 ?? I just hear "tros" with a rolling, Greek r.

τρως = you eat/are eating

σταματάς να τρως = you stop eating

Greek doesn't distinguish between present and present continuous. You can maybe work out from context more specifics regarding the action but it's not a distinction that matters.

The same as between τρώω and τρώμε. The first is singular, the second plural.

Maybe because there is just one syllable...