John _____ knowledge of radio just bystaying around the radio station.

Do you have a pencil——_________.

go Dutch for this supper, OK–No, _______ this time, as a reward for all your help

You should be _______ careful when you take the chemistry exam.—I agree. In this way, I will make _______ mistakes.

You’d be exposed to a lot ______ pollution if you moved to a town with pure water and air.