已知函数满足：，χ∈R（） A.A B.B C.C D.D

频率分布直方图中，小长方形的面积等于（　　）

A．组距

B．频率

C．组数

D．频数

中华全国商业信息中心2009年9月14日披露，我国城镇和农村居民家庭恩格尔系数已由1978年的57.5％和67.7％分别下降到2008年的37.9％和43.7％。这一变化表明

A．我国城乡居民的收入水平下降，总体消费水平降低

B．我国物价水平持续下跌，城乡居民的生活水平提高

C．我国居民的生存资料消费增加，发展资料消费减少

D．我国城乡居民消费结构在不断改善，生活水平提高

It will be hot—hot enough that most locals will have cleared town for cooler places. But because athletes competing at the 2004 Olympics have no choice but to stay in the hot weather, many plan to turn to science to stay cool.

Some will put their hands in ice water just before competing and nearly all will be wearing fabrics(织物) designed with hot weather in mind.

“Normally we warm up before exercise,”said Gordon Sleivert, director of sports science and medicine at the Canadian Sport Center in Victoria, British Columbia.“But in this case we're taking the warm out of warm up. It's like pre-cooling.”

Experts are predicting(预测) the average high this August in Athens will be 90 degrees Fahrenheit, with temperatures often reaching above 100(the average temperature in Sydney for the 2000 summer games was 64).

Although some events, such as the marathon, will start early(1 a.m.) to avoid hot weather, other competitors will be pushing their limits during high temperatures.       Drinking lots of water will help athletes keep cool, but humidity(湿度) remains a problem. The body's ability to cool down is weakened by damp air since sweat drips off the skin rather than evaporates(蒸发),resulting in dehydration(脱水) without the cooling.

“Getting hot is a real problem because when our brains heats up, the brain waves are more like when you're really sleepy. Everything feels harder,” said Sleivert.

小题1: The passage mainly tells us that _______.

A．why it is very hot in Athens

B．the hot weather is a big problem for Olympic athletes

C．how important science is to every athlete

D．the Olympics will be put off because of the hot weather小题2:The underlined sentence “other competitors will be pushing their limits during high temperatures”in the fifth paragraph means _______.

A．Olympic athletes will put off their competition time

B．some events in the Olympics will have to be put forward

C．competitors can't reach their limits in the hot weather

D．competitors will have to try their best to compete under any condition小题3:The following things will be likely to happen in the hot weather EXCEPT _______.

A．dehydration

B．being sleepy

C．that the blood in the body can become less and less

D．that the body's ability to cool down is weakened

为了防止（）等对人体的危害，对其应按照规定进行保管和使用。

A．腐蚀性物质

B．有毒物质

C．光线

D．高温

E．射线

校勘