Resolved questions
Teachers say 举手 to get kids to put their "hands up" to answer Qs, right? But how can I say "hands down"?

HAHA！ It's so easy you can say "放下手"，But I think that when you choice a studuet answer your quistion,other kids will put their hands by theirself

"把手放下", but it sounds weird since I dont see why the other kids would continue having their hands raised when someone has been picked to answer lol

I love italki, I learn something new each day. I never knew how to say that simple phrase, "放下手” 。

i don't think teachers will say "放下手" in the classroom.
they often say "手放下" in stead.
"手" is a "受事賓語".
"手" is always placed in the beginning of the sentence, ahead of the verb "放下",
to make a stronger tone and avoid ambiguous meaning.
"下手" means " to start to do something" or "to be next turn in a game"

Lyn，标准说法应该是“把手放下”，请研究下中文“把”的用法，比如“把枪放下”、“把钱交出来”，“把衣服穿上”。
如果你用英文语序“放下枪、交出钱，穿上衣服”也是对的，但经常不这么说。

you can say"放下"or"把手放下"...

呵呵，把手放下