"Я завтра зайду, хорошо?"
Translation:I'll drop by tomorrow, OK?
Yeah, just report it. There are enough possible English expressions it's not surprising they didn't get them all.
If you "drop by" or "drop in" somewhere, it means you visit just briefly — possibly informally, without being specifically invitation.
You might also hear "stop by" (ex. I'll stop by tomorrow.). It means the same thing.
Объясните пожалуйста, почему в вопросительном предложении на первом месте местоимение?
Это утвердительное предложение. Человек делает утверждение, а потом уточняет: "хорошо?" - и только эта часть является вопросительной.
Well, that's a tricky one. One might drop something on the floor and it breaks, meaning you were holding it and it accidentally fell from your hand. Rain and water form drops or droplets, a noun meaning a single particle of rain or water. Only when used with "by" does drop mean to visit briefly or unexpectedly. We also say "I'll drop you off", meaning driving in a car and taking someone to a place where they have some business to attend to, like a parent who "drops off" her child at school and then "picks up" the child when school is out.
The part of the sentence that's the question is the "OK?" part — the speaker is indicating that they're planning to come around tomorrow, and is checking that it will be all right.
Making "I'll drop by tomorrow" into a question like "Will I drop by tomorrow?" makes it sound like the speaker wants a prediction of the future (plus it wouldn't make sense with "OK" on the end, because there'd be nothing to confirm).