正确答案: A

纳秒

题目：下列选项中，不属于长度单位的是( )。

解析：纳秒是时间单位，一秒的十亿分之一。故选择A。B选项，纳米是长度单位，一米的十亿分之一。C选项，光年是长度单位，是光走一年的距离，相当于94611012公里。

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学习资料的答案和解析：

[单选题] Looking for a new weight loss plan? Try living on top of a mountain. Mountain air contains less oxygen than air at lower altitudes, so breathing it causes the heart to beat faster and the body to bum more energy. A handful of studies have found that athletes training at high altitudes tend to lose weight. Doctor Florian Lippl of the University Hospital of Ludwig-Maximilians-University Munich wondered how the mountain air would affect overweight individuals if they weren't doing any more physical activity than usual. Lippl and his colleagues invited 200verweight men to an environmental research station about 300 meters below the summit of Zugspitze, a mountain around 2,970 meters near the Austrian border. They were allowed to eat as much as they liked. The men also gave blood so that researchers could test for hormones(荷尔蒙) linked to appetite and fatness. At the end of the week, the men, whose mean weight starting out was 105 kg, had lost on average about 1.5 kg. The men's blood pressure also dropped, which the researchers attributed to weight lost. Exactly what caused the weight loss is uncertain. Loss of appetite is common at higher altitudes, and indeed the men ate significantly less than usual-about 700 calories fewer per day. Lippl also notes that because their consumption was being recorded, they may have been more self-conscious about what they ate. Regardless, eating less accounts for just 1 kg of the 1.5 kg lost, says Lippl. He thinks the increased metabolic rate, which was measured, also contributed to weight loss but cannot separate the different effects with the given data. Appetite loss at high altitudes could certainly be key, notes Damian Bailey, a physiologist at the University of Glamorgan, UK, who recently lost 11 kg during a 3-month expedition to the Andes in Chile. Unfortunately, for the average person there's no treatment that can resemble living at high altitude, says Lippl. The only alternative is a hypobaric chamber, which exposes subjects to low oxygen and isn't practical as a therapy. He says, half-jokingly,"if fat people plan their holidays, they might not go to the sea, but maybe to the mountains."

Lippl talks about the way of losing weight by spending holidays on mountains with ________.

casualness

解析：1.细节题。文章第一段第三句指出“Mountain air contains less oxygen than air at lower altitudes，so breathing it causes the heart to beat faster and the body to burn more energy.”即山上空气所含的氧气少于低海拔地区，所以呼吸时心脏跳动更快，身体也消耗更多的能量。由此可知心率与氧气含量多少有关。故选D。 2.细节题。根据文章第二段中“…researchers could test for hormones linked to appetite and fatness”可知hormones会影响食欲和肥胖，即体重。故选A。 3.细节题。第三段第二句指出“…the men ate significantly less than usual-about 700 calories fewer per day”由此可知，选项B正确。 4.细节题。根据文章第四段可知，Damian Bailey认同高海拔地区能影响人的食欲，从而影响体重．因为他在安第斯山脉考察的3个月里瘦了11公斤。故选D。 5.推断题。根据短文最后一句“He says，half-jokingly，if fat people…”中half-jokingly (半开玩笑地)可推断出Lippl在谈到通过去高原地区度假这种方式来减肥是随意的，开玩笑的。故选A。