听力原文：W: Mr. Smith, you must take these capsules every four hours without fail. M: It's 2 o'clock, and I just took my first one. I'll follow your instruction carefully so that I can get well soon. Q: When will the man take his next pill? (15) A．At two o'clock. B．At eight o'clock. C．At four o'clock. D．At six o'clock.