玉米是怎样进行自交？自交时应注意哪些问题？如何配制杂交种？

冬虫夏草的功效是（）

A.大补元气

B.接续筋骨

C.补益肺肾

D.补脾养心

E.补脾益肾

某淡黄色的颗粒状固体，其化学性质比较活泼，在通常状况下能跟许多物质发生化学反应。例如：它与CO₂反应时，只生成了Na₂CO₃和O₂，它与稀盐酸反应时，只生成了NaCl、H₂O和O₂。上课时，老师做了如下实验：

a．取少量的淡黄色的颗粒状固体投入到盛有少量水的试管中，可观察到产生了一种无色无味的气体；

b．再向试管中滴加几滴酚酞试液，可观察到烧杯中溶液变红。根据实验现象，回答下列问题：

（1）淡黄色的颗粒状固体中一定含有           元素。你做出这个判断的理由是                            。

（2）实验a中产生的气体，可用            法收集。

（3）同学们对实验a中产生的气体的组成看法不一，提出了以下几种假设： ①该气体是CO； ②该气体是H₂。请你推测该气体还可能是           （写化学式）。

（4）设计一个实验，证明你在（3）中的推测（写出简要操作步骤，反应现象和结论）。

简单分解爆炸所具有的特征是()。

A.不稳定单质爆炸物质

B.受震动而产生分解

C.受压而产生分解

D.在分解过程中产生热量

E.ABCD都不是

On Apr. 27, the Dean of Duke’s business school had the unfortunate task of announcing that nearly 10% of the Class of 2008 had been caught cheating on a take-home final exam. The scandal, which has cast yet another pall over the leafy, Gothic campus, is already going down as the biggest episode of alleged student deception in the business school’s history.
Almost immediately, the questions started swirling. The accused MBAs were, on average, 29 years old. They were the cut-and-paste generation, the champions of Linux. Before going to the business school, they worked in corporations for an average of six years. They did so at a time when their bosses were trumpeting the brave new world of open source, where one’s ability to aggregate (or rip off) other people’s intellectual property was touted as a crucial competitive advantage.
It’s easy to imagine the explanations these MBAs, who are mulling an appeal, might come up with. Teaming up on a take-home exam: That’s not academic fraud, it’s postmodern learning, wiki style. Text-messaging exam answers or downloading essays onto iPods: That’s simply a wise use of technology. One can understand the confusion. This is a generation that came of age nabbing music off Napster and watching bootlegged Hollywood blockbusters in their dorm rooms. "What do you mean " you can almost hear them saying. "We’re not supposed to share "
That’s not to say that university administrators should ignore unethical behavior, if it in fact occurred. But in this wired world, maybe the very notion of what constitutes cheating has to be reevaluated. The scandal at Duke points to how much the world has changed, and how academia and corporations are confused about it all, sending split messages.
We’re told it’s all about teamwork and shared information. But then we’re graded and ranked as individuals. We assess everybody as single entities. But then we plop them into an interdependent world and tell them their success hinges on creative collaboration.
The new culture of shared information is vastly different from the old, where hoarding information was power. But professors-and bosses, for that matter-need to be able to test individual ability. For all the talk about workforce teamwork, there are plenty of times when a person is on his or her own, arguing a case, preparing a profit and loss statement, or writing a research report.
Still, many believe that a rethinking of the assessment process is in store. The Stanford University Design School, for example, is so collaborative that "it would be impossible to cheat," says D-school professor Robert I. Sutton. "If you found somebody to help you write an exam, in our view that’s a sign of an inventive person who gets stuff done. If you found someone to do work for free who was committed to open source, we’d say, ’Wow, that was smart. ’ One group of students got the police to help them with a school project to build a roundabout where there were a lot of bike accidents. Is that cheating "
That’s food for thought at a time when learning is becoming more and more of a social process embedded in a larger network. This is in no way a pass on those who consciously break the rules. With countries aping American business practices, a backlash against an ethically rudderless culture can’t happen soon enough. But the saga at Duke raises an interesting question. In the age of Twitter, a social network that keeps users in constant streaming contact with one another, what is cheating

Why does the author cite the example of Stanford University Design School

下列对尖端探针用处的描述，错误的是

A．一般有两端弯曲度不同的工作端
B．用于检查龋洞和牙齿的感觉
C．工作端的角度可以任意改变
D．探针两端的尖端应保持锐利
E．用探针检查时必须有支点