Улий, я бы поставила на то, что ты используешь предлог in.

IN используешь если, например, дождь идёт)

А, спасибо! И мне до сих пор непонятно: меня учили at school - в школе, в смысле «учатся», in the school - в школе, в смысле «в здании», а ты употреблял «in school», что вообще непривычно.

Я тоже: нет-нет, а притыкаюсь с IN и AT, при всей теоретической осведомлённости

Никак не могу удалить предыдущий коммент, я его с голоса набирал, а он, гад, улетел...Раньше получалось...
Ули, когда я заметил, что в Штатах Future Continuous используют гораздо чаще чем FS, я спросил у американского инженера, как бы он сказал - I will wait for you, или I'll be waiting for you, он ответил, что по первому варианту. Хотя, мне кажется, что "If it takes forever, I will wait for you" - это только для долгой перспективы, да и то, с Continuous было бы лучше.
Поясни, пожалуйста

Получилось удалить, пришлось выйти и снова войти

In terms of SCHOOL: He's IN SCHOOL = he doesn't have a job because he's a student at the moment. He's AT SCHOOL = he's not home (teacher or student). He's IN THE SCHOOL = he's not outside. He's AT THE SCHOOL = (1) he's a teacher and he's working now (2) he's there for some reason - a visit, a presentation, a meeting, doing a repair, etc. (but NOT as a student)

О, спасибо, столько нюансов! То же самое относится к to school? Ученики скажут: I'm going to school. Их родители, которые идут в школу, на собрание, например: I'm going to THE (?) school. А учитель?

In terms of WAITING: "I'll WAIT at the apartment" is more of an offer to do so, whereas "I'll BE WAITING at the apartment" is an assurance - and can even be a threat in the right context. The use of the progressive starts a spoken stopwatch, letting the listener know that the action is in motion and the clock is ticking. Also, if the speaker is expressing an action in the progressive, it's common for you to match his tense to express what you WILL BE DOING simultaneously: (Wife on phone): Where are you? (Husband): I'm LOOKING at some lawnmowers at Ben's Garden Supply. (Wife): Oh, ok. I'll be WAITING at the café on the corner. Come get me when you're done. - In other words: while you're looking, I'll be waiting - we're both DOING two different things at the same time.

Tatiana: Correct! A student goes TO SCHOOL to learn, a parent goes TO THE SCHOOL for a meeting, and a teacher goes TO THE SCHOOL to teach. The phrase "go to school" has the meaning of учиться, so it's hard to apply it to a teacher, although in some contexts you do hear it. For instance, a teacher could potentially be asked by a detective "When you went to school that morning, did you notice anything different about any of the students?"

"Это тонкие штучки" - Михаил Жванецкий😃
Thanks a lot, Uly, you're a great teacher making up great examples

It's my absolute pleasure

Присоединяюсь!👍