English is a language that many people around the world _______not speak perfectly but _________at least understand．

--The man in a black suit _______ be our youth worker.--- I’m sure it _______ be him. I saw him in the laboratory building some minutes ago.

He____know the answer, but I’m not sure.

I hear you've got some new Australian coins. __________ I have a look?

—David is often absent from class.—Tell him he ________ answer for it if he goes on behaving like that.