对牙菌斑的描述准确的是（）。
A.牙菌斑结构中没有中间层
B.牙菌斑是一种生物膜
C.牙菌斑形成不需要经过获得膜形成阶段
D.非附着菌斑不属于牙菌斑
E.只有黏附到牙齿表面的才是牙菌斑
参考答案：B
解析：牙菌斑是口腔微生物在牙面上的主要存在形式，生物膜则是微生物黏附到固体表面形成的一种膜状结构的生态系，目前认为生物膜是微生物的主要存在形式，具有许多与浮游状态微生物不同的生物学性状，且有些与致病性密切相关。牙菌斑是一种典型的生物膜，因此现在许多研究从生物膜的角度来重新认识牙菌斑，因此考生既要知道生物膜这个比较新的概念，又要知道牙菌斑这个比较老的说法，并且了解它们之间的关系，不至于混淆。故答案为B。
被称为“传播学之父”的学者是（）。
请用化学用语填空。
（1）硫酸根离子：_______________。
（2）过氧化氢的化学式是：_______________。
（3）8个水分子：_______________。
（4）标出五氧化二磷中磷元素的化合价：_______________。
氢能被视为未来的理想清洁能源．如果汽车发动机使用氢能源来工作，效率可以达到60%．若一辆氢能源小轿车在从泰州行驶到上海大约260km的路程上获得的平均牵引力为840N，则它从泰州行驶到上海：（q氢=1.4×l08J/kg；）
（1）牵引力做的功是多少？
（2）汽车需要的总能量是多少？
（3）需要消耗的氢的质量是多少？
气敏电极可测量（）。
A.可直接测量某种气体
B.利用某一气体与溶液形成化学平衡后间接测量某一气体物质
C.测量溶液中气体的分压
D.直接在气相中测量某一气体分压
Whether to teach young children a second language is disputed among teachers, researchers and pushy parents. On the one hand, acquiring a new tongue is said to be far easier when young. On the other, teachers complain that children whose parents speak a language at home that is different from the one used in the classroom sometimes struggle in their lessons and are slower to reach linguistic milestones. Would a 15-month-old child, they wonder, not be better off going to music classes
A study just published in the Proceedings of the National Academy of Sciences may help resolve this question by getting to the point of what is going on in a bilingual child’s brain, how a second language affects the way he thinks, and thus in what circumstances being bilingual may be helpful. Agnes Kovacs and Jacques Mehler at the International School for Advanced Studies in Trieste say that some aspects of the cognitive development of infants raised in a bilingual household must be undergoing acceleration in order to manage which of the two languages they are dealing with.
The aspect of cognition in question is part of what is termed the brain’s “executive function”. This allows people to organise, plan, prioritise activity, shift their attention from one thing to another and suppress habitual responses. Bilingualism is common in Trieste which, though Italian, is almost surrounded by Slovenia. So Dr. Kovacs and Dr. Mehler looked at 40 “preverbal” seven-month-olds, half raised in monolingual and half in bilingual households, and compared their performances in a task that needs control of executive function.
First, the babies were trained to expect the appearance of a puppet on a screen after they had heard a set of meaningless words invented by the researchers. Then the words, and the location of the puppet, were changed. When this was done, the babies who speak only one language had difficulty overcoming their learnt response, even when the researchers gave them further clues that a switch had taken place. The bilingual babies, however, found it far easier to switch their attention — counteracting the previously learnt, but no longer useful response.
Monitoring languages and .keeping them separate is part of the brain’s executive function, so these findings suggest that even before a child can speak, a bilingual environment may speed up that function’s development. Before rushing your offspring into bilingual kindergartens, though, there are a few cautions. For one thing, these extraordinary cognitive benefits have been demonstrated so far only in “crib” bilinguals — those living in households where two languages are spoken routinely. The researchers speculate that it might be the fact of having to learn two languages in the same setting that requires greater use of executive function. So whether those benefits apply to children who learn one language at home, and one at school, remains unclear.
According to the author, rushing young children into bilingual kindergartens（）
A. may not speed up the executive function
B. is not useful to develop the brain
C. is useful for the executive function
D. may quicken them to reach linguistic milestones
