9310sectionA长阅读，很诡异的两道题， 我认为文中并没有提到相关的内容，请教大家！

无敌浩克OneUID: 3605802

One of the simplest and best known kinds of crystal is the ionic salt, of which a typical example is sodium chloride or ordinary table salt. The fundamental components of an ionic salt are ions: atoms or molecules that have become electrically charged by gaining or losing one or more electrons. In forming sodium chloride, for example, sodium atoms give up an electron (thereby becoming positively charged) and chlorine atoms gain an electron (thereby becoming negatively charged). The ions are attracted to one another by their opposite charges, and they stack together compactly, like tightly packed spheres.
Recently, scientists at Michigan State University created a new kind of crystal called an electride. In electrides, the anions (negative ions) are completely replaced by electrons, which are trapped in naturally formed cavities within a framework of regularly stacked cations (positive ions). Electrides are the first examples of ionic salts in which all these anionic sites are occupied solely by electrons.
Unlike other types of anions, anionic electrons do not behave as if they were simple charged spheres. In particular, because of their low mass and their tendency to interact with one another over great distances, they cannot be “pinned down” to any one location. Instead, they wander close to and among the atoms lining the cavity and interact with electrons in nearby cavities, perhaps changing places with them.
The properties of an electride depend largely on the distance between the cavities that hold trapped electrons. When the trapped electrons are far apart, they do not interact strongly, and so behave somewhat like an array of isolated negative charges. When they are closer together, they begin to display properties associated with large ensembles of identical particles. When they are still closer, the ensemble properties dominate and the electrons “delocalize”: they are no longer tightly bound within individual cavities but are more or less free to pass through the spaces within the frame-work of positive ions.
By synthesizing electrides from a variety of materials, one can vary the geometry of the anionic cavities and their relation to the surrounding cations. The resulting properties may make it possible for electrides to become a basis for economically useful new materials and devices. For instance, because the electrons in some electrides are very weakly bound, these crystals could be effective as photosensitive detectors, in which an impinging photon liberates an electron, resulting in a small electric current. The same weak binding could also make electrides useful in solar-energy converters and as cathodes in batteries. One obstacle is the tendency of electrides to decompose through reaction with air and water. Researchers are seeking ways to increase their stability.

26.        It can be inferred from the passage that an electride behaves most like a normal ionic crystal when the electride has which of the following features?
(A) The anionic cavities are widely separated.
(B) All of the trapped electrons are able to delocalize.
(C) The trapped electrons are liberated by impinging photons.
(D) The ions are tightly packed together.
(E) Most of the cations have lost their electrical charge.
这道题，完全没在文中找到和Normal ionic crystal有关的信息

27.        With which of the following statements regarding electrides would the author most likely agree?
(A) They have proven themselves to be of great commercial value.
(B) Their future commercial value is promising but uncertain.
(C) They are interesting but of no practical value.
(D) They have commercial value mainly in solar-energy applications.
(E) Their principal importance will lie in scientific research.
这道题也是，没有任何地方提到了商业价值。
看解析上写的真的很牵强，与其说科学家们继续研究这个领域说明他有商业价值，不如说他有科学重要性吧？虽然E的principal程度有些过了。

RevrieRiverUID: 3470313

26  a normal ionic crystal 其实就是指有别于electride的其他crystal，关键句有一下两句：
scientists at Michigan State University created a new kind of crystal called an
electride. （既然创造出了一种新的crystal，表明之前其他的crytal应是普通的，结合本文首句，更可以得此推论）

Electrides are the first examples of ionic salts。。。。。。by electrons. （eletricde是首例ionic salt）这也表明其他的ionic crystal应当是electride比照、比较的对象

27  关键词是在这句中出现的：The resulting properties may make it possible for electrides to become a basis for economically useful new materials and devices
economically useful， 经济效用
这就和商业价值联系起来了，后面for instance都是进一步举例说明electrides如何可能应用于实际领域

无敌浩克OneUID: 3605802

RevrieRiver 发表于 2015-5-31 16:28
26  a normal ionic crystal 其实就是指有别于electride的其他crystal，关键句有一下两句：
scientists a ...

非常感谢，第二题明白了~~还是看文章不仔细啊

第一题还是理解不通，新发现的全被电子占满的东西才是Electride，electride想要有和原来一样的表现，肯定不能使把这句话取非，变成不充满电子吧？这样完全就不是electirde了
答案选的A对应的原文说的是三种不同距离下electride的表现，也并没有说明normal对应的是怎样的？为什么就能推测是分的远的情况是Normal呢？

RevrieRiverUID: 3470313

无敌浩克One 发表于 2015-6-1 08:10
非常感谢，第二题明白了~~还是看文章不仔细啊

第一题还是理解不通，新发现的全被电子占满的 ...

第1题的题干问的是：

从文中推断，一个electride所具有的如下特征中，哪一种表现得最像正常普通的离子晶体？

换句话说，问的是electride在哪方面还和正常的离子晶体是一样的

因为是要求推断做题，所以无法从文中找到直接的对应信息。

谨慎起见，可以用排除法。
选项B说所有的被俘电子都能脱位，文中提到When they are still closer, the ensemble properties dominate and the electrons “delocalize”，这只是针对electride说的，不针对正常的离子晶体

选项C说所有的被俘电子由质子冲击解脱，文中提及the electrons in some electrides are very weakly bound, these crystals could be effective as photosensitive detectors, in which an impinging photon liberates an electron。这也是只针对electride说的

选项D所有的离子都簇拥一团，文中对应信息The ions are attracted to one another by their opposite charges, and they stack together compactly, like tightly packed spheres。这只是针对正常离子而言


选项E多数阳离子都丧失电荷，此内容与文中相关信息不符，which are trapped in naturally formed cavities within a framework of regularly stacked cations (positive ions).   及 more or less free to pass through the spaces within the frame-work of positive ions.
清楚说明electride里阳离子仍然带电，因为本文开始就提到atoms or molecules that have become electrically charged by gaining or losing one or more electrons. 选项本身就是错误的

所以排除法只能选A，electride和普通离子晶体的相同点在：阴离子孔都广泛分离

无敌浩克OneUID: 3605802

RevrieRiver 发表于 2015-6-1 09:31
第1题的题干问的是：

从文中推断，一个electride所具有的如下特征中，哪一种表现得最像正常普通的离子 ...

无比感谢！！！！！！
全明白了！！
PS，能麻烦你帮我看一下这个吗：https://bbs.gter.net/thread-1836232-1-1.html
一个句子结构没有弄明白