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问题 实验题

某研究小组进行一个有关兔水盐代谢调节的实验，以下为实验报告，请予以完善。

实验名称：兔的水盐代谢调节

(一)材料与方法

(1)家兔12只，2.5kg/只，随机分为3组(甲、乙及丙组)，每组4只。

(2)对甲组兔静脉滴注1.5％NaCl溶液，乙组滴注0.9%NaCl溶液，丙组滴注蒸馏水。滴注量均为200mL，0.5h滴完。

(3)从滴注开始收集测定2h内兔的尿液量。

(二)结果与分析

(1)甲、乙、丙三组兔平均尿量比较：___________。

(2)原因：______________。

(三)讨论

(1)实验设计时每组兔能否只用1只？___________。为什么？__________。

(2)有人认为需要增加1组兔才能使本实验设计更为完善，你认为对该组兔最有必要作何实验处理？______________。为什么？_____________。

答案

(二)结果与分析

(1)甲、乙、丙三组兔尿量比较：甲＜乙＜丙

(2)甲、乙、丙三组兔分别注入1.5%NaCl溶液、0.9%NaCl溶液和蒸馏水。丙、乙、甲三组兔细胞外液的渗透压依次升高，丙、乙、甲三组兔下丘脑的渗透压器所受的剌激依次升高，丙、乙、甲三组兔下丘脑分泌经垂体释放的抗利尿激素依次增多，丙、乙、甲三组兔肾小管、集合管等对原尿中的水重吸收的量依次增多。所以丙、乙、甲三组兔尿量依次减少。

(三)讨论

(1)不能    只用1只兔不能排除因个体差异造成的结果不准确

(2)  用这组兔作空白对照，不滴注任何液体    可以使甲、乙、丙三组兔的尿量有更好的比较基准

单项选择题

There is no question that the academic enterprise has become increasingly global, particularly in the sciences. Nearly three million students now study outside their home countriesa 57% increase in the last decade. Foreign students now dominate many U.S. doctoral programs, accounting for 64% of Ph. D. s in computer science, for example.
Faculty members are on the move, too. Half of the world’s top physicists no longer work in their native countries. And major institutions such as New York University are creating branch campuses in the Middle East and Asia. There are now 162 satellite campuses worldwide, an increase of 43% in just the past three years.
At the same time, growing numbers of traditional source countries for students from South Korea to Saudi Arabia (沙特阿拉伯), are trying to improve both the quantity and quality of their own degrees, engaging in a fierceand expensiverace to recruit students and create world-class research universities of their own.
Such competition has led to considerable hand-wringing in the West. During a 2008 campaign stop, for instance, then—candidate Barack Obama expressed alarm about the threat that such academic competition poses to U. S. competitiveness. Such concerns are not limited to the United States. In some countries, worries about educational competition and brain drains have led to academic protectionism. India, for instance, places legal and bureaucratic barriers in front of Western universities that want to set up satellite campuses to enroll local students.
Perhaps some of the anxiety over the new global academic enterprise is understandable, particularly in a period of massive economic uncertainty. But educational protectionism is as big a mistake as trade protectionism is. The globalization of higher education should be embraced, not fearedincluding in the United States. There is every reason to believe that the worldwide competition for human talent, the race to produce innovative research, the push to extend university campuses to multiple countries, and the rush to train talented graduates who can strengthen increasingly knowledge-based economies will be good for the United States, as well.

In the last paragraph, the author tries to emphasize that ______.

A. the academic enterprise has become global
B. academic competition has led to protectionism
C. worries over educational competition are understandable
D. educational protectionism cannot be justified
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不定项选择

(四)甲房地产开发公司(以下简称甲公司)以出让方式取得某住宅项目用地，委托拆迁后形成净地。甲公司委托乙房地产经纪机构(以下简称乙机构)代理该楼盘的销售。在预售过程中，甲公司报请城市规划管理部门批准更改了原规划。被拆迁人唐某预购了该项目一套住宅。在建设过程中，甲公司因资金紧张，将该项目部分用地转让给丙房地产开发公司(以下简称丙公司)。

下列关于规划、设计变更的表述中，正确的为（　　　　）。

A．甲公司应当自变更确立之日起7d内，书面通知买受人

B．甲公司如果未在规定的时限内通知买受人，买受人有权选择退房，且应由甲公司承担违约责任

C．规划、设计变更导致商品房状况变化，以及出现售房合同约定的其他影响商品房质量和使用功能情形的，买受人必须在变更通知到达之日起10d内作出是否退房的书面答复

D．买受人在变更通知到达之日起规定的时限内未作出是否退房的书面答复的，视同接受
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