何谓科研道德和科研道德修养？优良的科研道德品质具体表现在哪些方面？

两块大小、形状完全相同的金属平板平行放置，构成一个平行板电容器，与它相连接的电路如图所示．则（　　）

A．保持S接通，减小两极板间的距离，侧两极板间电场的电场强度减小

B．保持S接通，在两极板间插入一块绝缘介质，则极饭上的电量增大

C．断开S，减小两极板间的距离，则两极板间的电势差减小

D．断开S，在两极板间抽入一块介质，则两极板间的电势差增大

油炸食品、烧烤食品等被营养专家称作为“垃圾食品”，这是因为在制作过程中不仅产生大量有害气体污染环境，而且食物中还会产生一些强致癌物质，因此这类食品不宜多吃、常吃．如在食物的煎炸过程中会产生一种叫丙烯醛有害物质，它的化学式为C₂H₃CHO．根据其化学式完成下列问题：

（1）丙烯醛的相对分子质量为______．

（2）丙烯醛中碳、氢、氧三种元素的质量比为______．

（3）丙烯醛中氧元素的质量分数为______．

Part I Reading ComprehensionDirections: There are three reading passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are four suggested answers marked A, B,C and D.Choose the best answer to each question.Questions 1 to 5 are based on the following passage: ( 10 分 )Every artist knows in his heart that he is saying something to the public. Not only does he wantto say it well,but he wants it to be something which has not been said before. He hopes the publicwill listen and understand--he wants to teach them, and he wants them to learn from him. Whatvisual artists like painters want to teach is easy to make out but difficult to explain, because painterstranslate their experiences into shapes and colors, not words. They seem to feel that a certainselection of shapes and colors, out of the countless billions possible, is exceptionally interesting forthem and worth showing to us. Without their work we should never have noticed these particularshapes and colors, or have felt the delight which they brought to the artist. Most artists take theirshapes and colors from the world of nature and from human bodies in motion and repose; theirchoices indicate that these aspects of the world are worth looking at, that they contain beautifulsights. Contemporary artists might say that they merely choose subjects that provide an interestingpattern, that there is nothing more in it. Yet even they do not choose entirely without reference to thecharacter of their subjects. If one painter chooses to paint a gangrenous (生坏疽的) leg and another alake in moonlight, each of them is directing our attention to a certain aspect of the world. Eachpainter is telling us something, showing us something, emphasizing something---all of which meanthat, consciously or unconsciously, he is trying to teach us.

Contemporary artists choose subjects

A．without reference to the character of their subjects

B．that only provide the interesting pattern

C．that there is no meaning in it

D．partly for the meaning of the subjects

低位小肠梗阻的特征是（）

A.腹部肠形不明显

B.水电解质紊乱出现较早

C.呕吐不频繁

D.腹胀不明显

E.呕吐物无粪臭味

真菌既不含叶绿素，也没有质体，是典型的异养生物。