Li Lei's parents ______ doctors.
—I think sixteen-year-olds should be allowed to drive.— ______. They aren’t serious enough at that age.
—Let’s visit the sick children in hospital and ______.—OK, let’s go.
—What are you listening to?—A song by Huo Zun. It ______ beautiful.
—I’m busy with my schoolwork these days.—That’s great! You won’t get good grades ______ you work hard.
—Whose pencil box is this?—It _____ be Tom’s. It has his name on it.