[填空题]Part 2
Questions 9-18
·Read the following article and answer questions 9-18 on the next page.

Train Your Body into Knowing When It’s Time to Sleep

1. A good night’s sleep actually starts in the morning. The second your eyes open, light shoots down the optic nerve and into the brain’s biological clock. There it stimulates the production of hormones that regulate growth, reproduction, eating, sleeping, thinking, remembering—even how you feel from minute to minute. "Sunlight activates the brain," says Frisca L. Yan-Go, M.D., medical director of the UCLA Sleep Disorders Center. And activating it at the same time every morning synchronizes your body’s biological clock. Then your body has a clear direction that at midnight it’s supposed to be asleep and at noon it’s supposed to be awake. Wake up at a different time every day and the clock is out of order. You feel sleepy and hung over fo