计算题：有一个45号工字钢（A3材质）应变形需矫直，现有200t液压千斤顶一个，并有

土壤是在岩石经过长期的风吹雨打、冷热交替和生物的作用下逐渐形成的，是人类宝贵的自然资源．

（1）土壤除了能固定植物体外，还能为植物生长提供水分、空气和______．

（2）选择干燥的土地，取棱长为10厘米的一块立方体土壤和棱长为10厘米的一块立方体铁块，把它们分别放人两个大烧杯中，沿烧杯壁缓慢向烧杯内注水，直到水面把土壤和铁块全部浸没为止，然后比较所加入的水量．此实验的目的是______．

男性，25岁，腹痛2天急诊入院。患者于48小时前突然发作全腹痛，以右下腹更明显，为阵发性绞痛，伴有肠鸣，多次呕吐，开始为绿色物，以后呕吐物有粪臭味。两天来未进食，亦未排便排气，尿少，自觉发热。三年前曾作过阑尾切除术。查体：急性病容，神智清楚，血压100/60mmHg，脉搏132次／分，体温37.5℃，皮肤无黄染，干燥，弹性差。心肺正常，腹膨隆，未见肠型，全腹触诊柔软，广泛轻压痛，无反跳痛，未触及肿块，肝脾不大，肠鸣音高亢，有气过水音。辅助检查：血红蛋白160g/L，白细胞10.6×10/L，尿常规阴性。腹部透视有多个液平面。

患者的诊断为()

A.急性肠梗阻（机械性、粘连性、低位）

B.上消化道穿孔

C.肠扭转

D.肠系膜血管血栓形成

E.大网膜扭转

临床麻醉中上呼吸道梗阻最常见的原因是（）。

A.舌后坠

B.分泌物过多

C.误吸

D.支气管痉挛

E.气管导管打褶

C

　　The villagers of Yaluma in Southern Mexico are some of the poorest people in the country. But now they have an extra source of income.They are being paid to grow and develop forests by the organization in charge of Formula One racing (一级方程式赛车),which pumps 5,500 tons of carbon dioxide (CO2) into the air every year.The idea is that the forests being planted around Yaluma will absorb this amount. It will also provide people there with money while wiping out motor racing's environmental debt.

　　Projects like this go under the name of "carbon trading". The basic idea is that governments and companies can buy the right to pump CO2 into the air by investing in green projrvyd. They can buy so-called "carbon credits" from countries which have succeeded in reducing CO2 emissions(排放物).

　　Supporters of carbon trading say that it brings money and green technology to poorer countries.It also provides a new way of doing busingess and spreading prosperity. They point out that the process of globalization will give people everywhere the most possible choice of products and services. Carbon trading is just another way of bringing that about. It is a "win - win" situation.

　　Opponents argue that nature comes before lifestyle. CO2 emissions need to be reduced, not bought and sold. And they believe that the rich world should lead the way.People might be willing to change the way they live to help save the world, but not to help the rich countries keep a lifestyle that depends on pollution.

　　Supporters of carbon trading believe in unlimited growth.Opponents believe that nature sets limits to the choices we make on how to live.It is "don't do " against "can do". It is life against lifestyle.

　　It is believed that modern lives are about choice.For example,the world can choose to take the danger of global warming seriously.And the sooner we choose to do it, the more choices we have about what to do next and the more time we have to do it in. We can also choose to pay no attention to the danger of global warming to keep our lifestyles. Then one day nature may give us no choice at all,and maybe not much of a life,either.

　　64.Carbon trading is discussed in the text in order to show the importance of ______ .

　　　A.reducing pollution B.taking care of forests

　　　C.spreading prosperity D.choosing lifestyle or nature

　　65."Carbon credits" may be used to ______.

　　　A.get the right to pump CO2 into the air

　　　B.get the right to pump CO2 into poor countries

　　　C.learn about the way to reduce CO2 emissions

　　　D.improve the way to reduce CO2 emissions

　　66.We can infer from the text that in the "win - win" situation _____.

　　　A.rich countries perform their duty to help poor countries

　　　B.poor countries get what they need from rich countries

　　　C.both rich countries and poor countries get what they need

　　　D.rich countries learn from poor countries in reducing pollution

　　67.In the opinion of people who are against carbon trading,the rich countries should ____.

　　　A.guide poor countries in reducing CO2 emissions

　　　B.show by example how to reduce emissions

　　　C.offer more help to save the world

　　　D.improve their lifestyles to keep the world clean

下列关于变异系数的说法，正确的是（）。

①变异系数用来衡量单位预期收益率所承担的风险

②变异系数越大，表示投资项目风险越大，越不应该进行投资

③项目A的预期收益率为7.5%，标准差l0%，则其变异系数为0.75

④项目B的预期收益率为4%，标准差3%，则其变异系数为0.75

A.①②③

B.①③④

C.①②④

D.②③④