1. 【2015·重庆】完形填空
阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。
Imagine the first days in a new time zone. Slow to respond to the ____1____, your body clock is confused. You're sleepy all day, but when it's time for bed, you can hardly fall asleep. Obviously you're ____2____ jet lag(时差反应).