阅读理解。 Younger adults who get either little sleep or a lot of it may see a greater increase in their waistlines (腰围) over time, a study suggests. The study included 332 African-American and 775 Hispanic-American (西班牙美国人) men and women aged 18 to 81. The researchers measured their abdominal(腹部的) fat, at the start of the study and again five years later. Among the people younger than 40 in the research, the study found, those who said they slept for five hours or less each night gained more fat than those who averaged six or seven hours of sleep. Those who slept eight hours or more in bed each night also showed a bigger fat gain-but it was not as much as that seen in 'short sleepers ' . The findings, according to the lead researcher Dr Kristen, support the belief that sleep habits affect weight, and health in general. ' Sleep is an important part of your overall health-not just in whether you're tired during the day,' he said. As for why sleep time might affect abdominal-fat gain, there are several facts: People who get too little sleep may be too tired during the day to exercise, while those who spend a lot of time in bed may spend less time being active, comparing to people who sleep fewer hours. Research also suggests that sleep loss changes people's appetite-regulating hormones (胃口调节荷尔蒙)-which could, in theory, make them overeat. What's more, depression, which is a feeling of sadness that makes people think there is no hope for the future, could also be a reason. He also noted that it often affects people's sleep and has been linked to weight gain. 1. ___ will get less fat gain according to the passage. A. Younger adults who sleep for five hours or less B. People who sleep more than 8 hours every day C. Younger adults who are from Africa or America D. People who sleep about six or seven hours a day 2.  The underlined word 'that' refers to____. A. a fat gain B. sleep habits C. too little sleep D. too much sleep 3. What can we leam from the passage? A. The more we sleep, the more energetic we will be. B. The less we sleep every day, the less fat we will get. C. Those who are in sadness could easily get a bigger fat gain. D. The African and Hispanic adults easily get a greater weight gain.