单选题06．散粒材料的堆积体积内，颗粒之间的空隙体积所占的比例称为（）

>> 国家开放大学 / 建筑材料（A）

国家开放大学 / 建筑材料（A）

单选题06．散粒材料的堆积体积内，颗粒之间的空隙体积所占的比例称为（）

A. 孔隙率
B. 填充率
C. 空隙率
D. 密实度

积分

建筑材料（A）

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题干二、阅读理解：阅读下面的短文，根据文章内容从A、B、C三个选项中选出一个最佳选项。 Car crashes are the top killer of American teenagers. Most of the crashes result from distracted driving—not paying attention to the road. Ryan Didone was a fifteen-year-old passenger in a car that hit a tree. He was one of the nation's more than thirty thousand victims of traffic crashes in 2008. Nearly four thousand deaths, about twelve percent involved drivers age fifteen to twenty. Ryan's father, Thomas Didone, is a police captain in Marylan. "It was an inexperienced, immature driver driving at night with a carload of kids. He was distracted, he was going too fast, and it ended up causing one death and some seriously injured." He shares the story of his son's death to help educate teens and their families about distracted driving. Jim Jennings from the Allstate Insurance Company says the number one cause of distracted-driving accidents is the mobile phone. He says talking on the phone or reaching for it is like drinking four beers and driving. "If you're texting while driving, you are twenty-three times more likely to get into an accident than somebody who isn't." Government and private groups are using public service announcements and events to bring more attention to the problem. For example, the insurance industry recently held a safety event for teen drivers. At first, nineteen-year-old Kevin Schumann easily avoided large, inflatable dolls thrown in front of the car to represent children. He also avoided orange cones representing the edge of the road. Then, as part of the test, he started texting. He hit several cones and at least one doll. "That's what really opened up the experience for me to prove how bad it is to really text and drive." Debbie Pickford of Allstate Insurance says teens are especially at risk from distracted driving —and not just because they lack experience on the roads. "According to the research, teens don't really have fully developed brains until they’re twenty-five years old. You put those two things together and you get a much,much higher risk." A new law proposes a graduated driver licensing system. Graduated means teenagers start with restrictions like on night driving and numbers of passengers. They could not get a full driver's license until age eighteen. 1.According to the passage, 回答ABC正确获得1.00分中的1.00分 is the most likely to lead to a traffic accident while you are driving． A．texting on the mobile phone B．reaching for a cell phone． C．talking on the mobile phone 2. We can learn from the second paragraph that回答ABC正确获得1.00分中的1.00分． A. drivers who resulted in nearly 4,000 deaths are teenagers B. over 30,000 victims have died from traffic crashes so far C. it was at night that Ryan Didone died from a car accident 3. A safety event held by insurance industry was meant to 回答ABC正确获得1.00分中的1.00分. A．attract more teenagers to take part in it B．draw enough attention to teenagers' distracted driving C．make more teenagers practice avoiding large barriers 4. The passage is probably followed by a concluding paragraph about 回答ABC正确获得1.00分中的1.00分． A．much higher risk B．teen brain development C．measures to be taken 5. Of all the following, which is the best title for the passage?回答ABC正确获得1.00分中的1.00分 A．Car Crashes —the Top Killer. B．Distracted Driving —Let's Avoid! C．Drunken Driving — Dangerous Enough！理工英语1

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