【正确答案】 B

【答案解析】[解析] 26-29
How much sleep is enough sleep? (26)Well, adults need adults seven to eight hours of sleep per night. Some people think they can sleep for only three hours or even twenty minutes each night and feel fully rested. Supposedly, Albert Einstein only slept for a few hours every night and took many short naps during the day. That may have worked for him, but most people need their sleep. In fact, sleep deprivation can have serious negative health effects.
How? Well, you might be surprised to learn that sleep affects our weight. Doctors in the United States found that (27)people who don't get enough sleep have a higher chance of being obese. Sleep deprivation disturbs the hormones that tell us when to stop eating. So if you'd like to lose a few pounds, don't try the newest starvation diet, just try getting more sleep!
Sleep deprivation can also lead to mental and emotional problems. Researchers have found that people have a hard time making good decisions when they are fatigued. (28)Some people in high-stress jobs have made dangerous mistakes while working. Because of this, the airline and health industries have strict rules about the amount of sleep their employees must have.
When we sleep, we dream. Dreams are usually fun to think about and remember. But they serve a more important function. In fact, dream deprivation is as problematic as sleep deprivation. (29)When we dream, our bodies release certain hormones that help us relax. People who don't dream suppress these hormones.
Q: How much sleep is enough for ordinary people every day?

[答案详解] 短文中提到成人一般每晚需要七到八个小时的睡眠。故选B)项。

【正确答案】 B

【答案解析】[解析]
Q: How does sleep affect people's weight?

[答案详解] 一短文中提到睡眠不足的人肥胖的几率更大。故选B)项。

【正确答案】 C

【答案解析】[解析]
Q: Why are there rules about the amount of sleep employees must have in the airline and health industries?

[答案详解] .短文中提到做高压力工作的人曾因疲劳在工作时犯下很危险的错误，因此航空和医疗行业严格规定员工的睡眠时间。故选C)项。

【正确答案】 A

【答案解析】[解析]
Q: What do we know about dreams from the passage?

[答案详解] 短文中提到做梦时身体会释放荷尔蒙帮助我们放松。故选A)项。