P、V操作属于A．机器指令 B．系统调用命令 C．低级通信原语 D．作业控制命令

2008年8月将在中国北京举办第29届奥运会,这是世界盛事,更是中国人民的盛事.奥运会首先出现于古代希腊,下列有关古代希腊的说法正确的是

①留给我们最宝贵的财富是雅典的民主政治 ②西方的人文主义思想最早出现于此 ③全体公民都能享受到民主权利 ④凭借有利的地理位置发展工商业

A．①②③④

B．①②④　　　

C．②④

D．①③④

C

Organic food has no nutritional or health benefits over ordinary food，according to a major study．

Researchers from the London School of Hygiene & Tropical Medicine said consumers were paying higher prices for organic food because of its imagined health benefits，creating a global organic market worth an estimated $48 billion in 2007．

A systematic review of 162 scientific papers published in the scientific literature over the last 50 years，however，found there was no significant difference．

“A small number of differences in nutrient content were found to exist between organically and conventionally(通常)produced foodstuffs，but these have nothing to do with public health，” said Alan Dangour ，one of the report's authors．

“Our review indicates that there is currently no evidence to support the selection of organically over conventionally produced foods on the basis of nutritional superiority ．”

The results of research，which was commissioned by the British government’s Food Standards Agency，were published in the American Journal of Clinical Nutrition．

Sales of organic food have fallen in some markets，including Britain，as a slowdown in economic growth has led consumers to cut back on purchases．

The Soil Association said that growth in sales of organic products in Britain slowed to just 1.7percent，well below the average annual growth rate of 26 percent over the last decade．

64. Why does organic food cost more than conventionally produced food?

A. Because people think they are much healthier.    B. Because they are more delicious.

C. Because people prefer organic food.            D. Because they sell better.

65. According to the study，organic food is_________ than conventionally produced food.

A. much healthier           B. better       C. no healthier           D. less healthier

66. Sales of organic food have fallen because of___________.

A. high price            B. economic decline       C. bad service           D. poor quality

67. Where can you find this passage in a newspaper?

A. Economy            B. Science．      C. Food & Nutrition      D. Fashion

1900年（）的订立，使鸦片税收成为清政府偿还“庚子赔款”的重要来源。

A、马关条约

B、辛丑条约

C、北京条约

在适宜的温度、水分和CO₂保证供应的情况下，测得不同植物光合作用量值（用环境CO₂减少量来度量）如下图所示。下列四种叙述中不正确的是（）。

A．在该实验条件下，影响植物CO₂吸收量增加或减少的主要因素是光

B．在同等光照条件下，玉米比小麦的光合作用产量高

C．在同等光照条件下，小麦、玉米和高粱等农作物光合作用量值比阳生草本的要高

D．无论环境条件如何变化，阴生植物总是比阳生植物光合作用的效率低

若偏态分布资料一端或两端无确切的数值，描述其离散程度的指标是（）

A．几何均数 

B．四分位数间距 

C．中位数 

D．算术均数 

E．标准差