问题 探究题

小明通过课外阅读了解到:驾驶员驾车遇到紧急情况时,从决定停车,直至右脚刚刚踩在制动器踏板上,在这段反应时间内,汽车按原速度行驶的距离称为反应距离,从踩紧踏板到车停下的距离称为刹车距离.普通人正常的反应时间,平均约0.5-1.5s;酒后驾驶的反应时间则增加2-3倍.为确保人民的生命财产安全,新的道路交通安全法对酒后驾驶给予了十分严厉的处罚.

(1)为了测试一下人正常的反应时间,小明和同学小华、小惠、小刚设计了一个测试实验,如图甲所示.小明竖直拿着尺的上端,被测试的同学在尺的正下端位置张开手指,当被测试者看到小明松开手将尺自由落下时,被测试者迅速用手抓住尺.比较手抓尺部位的高低,就能判断人的反应快慢.通过实验,小华、小惠和小刚分别抓住了尺上的A、B、C三点,如图乙所示.

你认为谁的反应更快?              

(2)除了驾驶员不要酒后驾驶外,小明想:如果是阴雨天气,路面被雨水打湿了,刹车距离会受到影响吗?于是找来了实验器材:木板、斜面、小车、刻度尺、水,进行实验验证这一问题.请你帮他设计实验过程:

(3)完成了上述实验之后,小明又想探究一下,刹车距离还可能受到哪些因素的影响.请你帮他再提出一个合理的,有价值的探究问题:___________________________ .

答案

(1)小华

(2)在斜面底端的水平面上放上木板,让小车从斜面的某一确定的位置由静止滑下,用刻度尺先后测出木板被水打湿前后,小车在木板上滑行的距离,进行比较.

(3)刹车距离是否与车速有关

材料题
完形填空

Don't blame genes for aging facial skin. A new study of twins suggests you can   1  those coarse(粗糙的) wrinkles, brown or pink spots, and dilated(膨胀的) blood vessels on too much time in the sun, smoking, and being overweight.

Because twins share genes, but may have  2 exposures to environmental factors, studying twins allows an, "opportunity to control for genetic susceptibility(敏感性)," Dr. Elma D. Baron, at Case Western Reserve School of Medicine in Cleveland, Ohio, and colleagues  3 in the latest issue of Archives of Dermatology.

Their analysis of environmental skin-damaging factors in 65 pairs of twins hints that skin aging is  4 more to environment and lifestyle than  5  factors.

But when it   6  skin cancer, the researchers say their findings support previous reports that   7  environment and genes affect skin cancer risk.

Baron's team   8  facial skin of 130 twins, 18 to 77 years old, who lived 9  in the northern Midwest and Eastern regions of the U.S. who were  10  the Twins Days Festival in Ohio in August 2002.

At this time, each of the twins also  11   reported how their skin burned or tanned  12   sunscreen(防晒霜), their weight, and their history of skin cancer, smoking, and alcohol drinking.

The study group   13  of 52 fraternal and 10 identical twin pairs, plus 3 pairs who were unsure of their twin status. Identical(同卵的) twins share all of their genes and fraternal twins share only about half.

From these data, the researchers  14 strong ties, outside of twin status, between smoking, older age, and being overweight, and having facial skin with evidence of environmental  15 

 16  contrast, sunscreen use and drinking alcohol appeared correlated with   17   skin damage.

Baron and colleagues say the current findings, which highlight ties between facial   18 and potentially avoidable  19  factors -- such as smoking, being overweight, and   20  overexposure to the sun's damaging rays -- may help motivate people to minimize these risky behaviors.

(    ) 1. A. blame                     B. owe                 C. take                 D. bring

(    ) 2. A. same                       B. different           C. similar             D. common

(    ) 3. A. explain                    B. confirm            C. declare             D. shout

(    ) 4. A. equal                             B. related              C. close                D. strict

(    ) 5. A. characteristic           B. personal           C. natural             D. genetic

(    ) 6. A. comes to                 B. talks of             C. refers to           D. gets to

(    ) 7. A. all                          B. neither             C. both                 D. either

(    ) 8. A. examined                B. checked            C. inspected          D. interviewed

(    ) 9. A. most                       B. usually             C. mostly              D. always

(    ) 10. A. joining                  B. representing      C. attending          D. remarking

(    ) 11. A. separately              B. lonely              C. commonly               D. truly

(    ) 12. A. with                             B. on                    C. in                    D. without

(    ) 13. A. consisted                      B. made up         C. contained        D. included

(    ) 14. A. documented           B. recorded           C. reported           D. noted

(    ) 15. A. damage                 B. exploration       C. protection         D. material

(    ) 16. A. In                         B. By                   C. As                    D. At

(    ) 17. A. lesser                    B. more                C. no                    D. fewer

(    ) 18. A. look                             B. aging                      C. expression               D. wrinkle

(    ) 19. A. environmental               B. genetic             C. emotional         D. psychological

(    ) 20. A. protected                      B. planned            C. unprotected       D. prevented