Can you please tell me if the following expressions are possible?

1) Would it be all right with you if I got my book from the other room?
I left it in my backpack.
2) Can you wipe the blackboard off?
3) You should return the book to the library in two week's time.
4) Can you check the following words: a tablet for the cough: better a cough lozenge, the counter of frozen food (not the frozen food counter), the check-out desk or counter?, to put the ankle in a cast, to put a cast on the counter but Not to cast the ankle?

Thank you

#s 1 and 2 are fine.

In #3, use weeks' (plural possessive) since it's two of them.

#4 --
cough lozenge or cough drop (not tablet)
frozen food counter
check-out desk, or simply "at the check-out"
put the ankle in a cast (not "counter" or "plaster" in American English)