David, turn off the TV _____ no one is watching it.—But it _____ off already! The music is from the radio.[ ]

If our government _______ attention to controlling food safety now, our health _______ in danger.

Try to sing some English songs, you’ll find it interesting _____ a foreign language.

He has been in the USA .

Do you have a small mouth?—No, I don’t. I have a ____ one.