He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.

 —Mr. Smith, why are you always asking me to do the difficult work?—Because you _______ do such a thing and nobody else is fit for it.

Some “healthy” habits, such as shower every day and sitting on the loo, _____ be bad for you.

---Fifty dollars for such a T-shirt！You_____ be joking！--- I’m serious. It’s made of silk.

—Peter doesn’t mind lending you his camera.—He __________. I’ve already borrowed one.