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第二篇 Cell Phones Increase Traffic, Pedestrian Fatalities Cell phones are a danger on the road in more ways than one. Two new studies show that talking on the phone while traveling, whether you’re driving or on foot, is increasing both pedestrian deaths and those of drivers and passengers, and recommend crackdowns on cell1 use by both pedestrians and drivers. The new studies, lead-authored by Rutgers University, Newark, Economics Professor Peter D. Loeb2, relate the impact of cell phones on accident fatalities to the number of cell phones in use, showing that the current increase in deaths resulting from cell phone use follows a period when cell phones actually helped to reduce pedestrian and traffic fatalities. However, this reduction in fatalities disappeared once the numbers of phones in use reached a "critical mass" 3 of 100 million, the study found. These studies looked at cell phone use and motor vehicle accidents from 1975 through 2002, and factored in4 a number of variables, including vehicle speed, alcohol consumption, seat belt use, and miles driven. The studies found the cell phone-fatality correlation to be true even when including factors such as speed, alcohol consumption, and seat belt use. Loeb and his co-author determined that, at the current time, cell phone use has a "significant adverse effect on pedestrian safety" and that “cell phones and their usage above a critical thresholds adds to motor vehicle fatalities." In the late 1980s and part of the 1990s, before the numbers of phones exploded, cell phone use actually had a "life-saving effect" in pedestrian and traffic accidents, Loeb notes. "Cell-phone users’ were able to quickly call for medical assistance when involved in an accident. This quick medical response actually reduced the number of traffic deaths for a time," Loeb hypothesizes. However, this was not the case when cells were first used in the mid-1980s, when they caused a "life-taking effect" among pedestrians, drivers and passengers in vehicles. In those early days, when there were fewer than a million phones, fatalities increased, says Loeb, because drivers and pedestrians probably were still adjusting to the novelty of using them, and there weren’t enough cell phones in use to make a difference in summoning help following an accident, he explains. The "life-saving effect" occurred as the volume of phones grew into the early 1990s, and increasing numbers of cells were used to call 911 following accidents, leading to a drop in fatalities, explains Loeb. But this life-saving effect was canceled out6 once the numbers of phones reached a "critical mass" of about 100 million and the "life-taking effect" - increased accidents and fatalities outweighed the benefits of quick access to 911 services, according to Loeb. Loeb and his co-authors used econometric models to analyze data from a number of government and private studies. He and his co-authors recommend that governments consider more aggressive policies to reduce cell phone use by both drivers and pedestrians, to reduce the number of fatalities.

A. show that talking on the phone while driving or walking in the street increases deaths of drivers and pedestrians.
B. show that talking on the phone while driving increases pedestrian deaths.
C. recommend that strict measures be taken to restrain cell phone use.
D. both A and C.

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人脑就是通过这个惊人的微观网络开展它的工作的。每个神经元接收到数千个刺激信号,并立刻决定是中止它还是将信号传给它众多的邻居。在这个过程中,将有数千亿个不同的传输方向。这是人脑与电脑的根本不同。一个电脑基本上是一维的:它操作一个计算,然后是第二个和第三个,是一种线性的形式。它不能同时操作大量不同的工序,并将它们综合平衡而得到一个完整的结果,但人脑能有效地像数千万台电脑同时工作一样地运转。对“人脑能有效地像数千万台电脑同时工作一样地运转”这句话的含义,理解最准确的一项是( )。

A. 人脑可以同时开展大量的线性形式的计算,就好像有千万台电脑同时进行计算一样
B. 人脑通过它的微观网络系统开展工作,就犹如将千万台电脑联网进行某一项工作
C. 人脑可以同时操作不同的工序,就好像数千万台电脑同时进行不同的工作一样
D. 人脑能将不同的信息综合平衡得出一个完整的结果,就好像数千万台电脑同时处理不同信息得出结果一样

介入医学是一门融医学影像学和临床治疗学为一体的新兴边缘学科,涉及人体消化、呼吸、心血管、神经、泌尿、骨骼等多个系统疾病的诊断和治疗。生物医学材料的研究和发展对介入医学的普及和发展起着举足轻重的作用。尤其是为一些不治之症或难治之病,如癌症、心血管疾病等开拓了新的治疗途径,而且简便、安全、有效、并发症少。在介入疗法中,插入身体的导丝、导管壳、导管、血管支架、球囊导管,以及人体内各腔道支架,都是由医用生物材料制成的。 下列各项中,不符合本段关于介入医学描述的是( )。

A. 介入医学为不治之症开辟了新的治疗途径
B. 介入医学与医用生物材料本身的研究和发展相关
C. 介入医学提供血管和各腔道的支架,植入患者体内
D. 介入医学操作简便且并发症少

甲壳素又名蟹壳素、聚乙酰氨基葡萄糖等,是一种维持和保护甲壳动物和微生物躯体的线性氨基多糖,广泛存在于节足动物类的翅膀或外壳中。壳聚糖又称聚氨基葡萄糖、可溶性甲壳素,是由甲壳素经脱乙酰化反应转化变成的分子量为12—59万的生物大分子。壳聚糖具有很好的抗菌活性,将其添加到固液食品中,既会对汁液有一定的澄清作用,又可以起到防腐保鲜的作用,而且,由于壳聚糖只能溶解在弱酸中,因此特别适合酸性或低酸性的食品保鲜。 以下关于壳聚糖的描述错误的是( )。

A. 是分子量为12—59万的生物大分子
B. 是源于脱乙酰化反应后的甲壳素
C. 可溶于任何浓度的酸性溶液
D. 从蜘蛛和甲壳类动物的外壳中可制取出壳聚糖

汉代乐府所掌管的诗歌可以分成两大类:一类是专门供朝廷祭祀天地、宗庙的所谓“郊庙歌辞”,汉高祖唐山夫人所作的《安世房中歌》和武帝时所作的《郊祀歌十九章》都属于这一类,犹如《诗经》的“颂”。另一类是从各地采集来的“俗曲”,它们是一些流传于民间的无名氏的作品,是西汉乐府诗的精华,因为它们来自民间,所以后世称之为乐府民间歌辞,或乐府民歌。 文中说乐府的“郊庙歌辞”犹如《诗经》的“颂”,对这样类比的用意,理解不恰当的一项是( )。

A. 说明汉乐府的“郊庙歌辞”是专门为皇家服务的庙堂文学
B. 说明汉乐府的“郊庙歌辞”内容多是歌颂祖先和神灵的功德
C. 说明汉乐府的“郊庙歌辞”是有较高艺术水平的文人创作
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