下列关于计算机系统工作原理的叙述中,正确的是( )。A.中央处理器直接对存储器中的

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问题:

下列关于计算机系统工作原理的叙述中,正确的是( )。

A.中央处理器直接对存储器中的数据进行处理

B.运算器完成解释和执行指令的工作

C.中央处理器可以从输入设备中得到控制指令

D.程序和数据均存放在存储器中

考点:计算机等级考试数据库技术三级数据库技术笔试
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用简洁明确的语言表述下面一段文字中画横线句子的意思。不超过20个字。

有人对"出类拔萃"这一成语中的"拔萃"作了如是诠释:认为一个人"出类"既难,"拔萃"则更需要付出双倍艰辛,冒着双倍的风险,因为"拔萃"往往需要或意味着"广拔"掉某些拥戴者既有的智慧成果的桂冠,往往同时宣布着另一项领衔成果的出现,或对某项既定结论的突破。

答:                                                                

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下列属于一类疫病的是()。

A.狂犬病

B.猪瘟

C.高致病性蓝耳病

D.高致病性禽流感

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The use of chemicals in almost all areas of life has become a commonplace phenomenon. There is growing evidence, however, that chemicals in the environment, including pesticides, may contribute to some illnesses. While studies are still being conducted, preliminary conclusions point to the verdict that such chemicals are indeed negatively impacting those humans to whom they are exposed.

Children are especially vulnerable to toxic substances. Pound for pound, they eat, drink and breathe more than adults, all of which exposes them more heavily to those chemicals to which most individuals encounter on a daily basis. Furthermore, their bodies are still in developing stages, exacerbating the negative effects of those chemicals, which negatively impact them.

Of 50 types of pesticides commonly used in American schools, a study conducted by the National Coalition Against the Misuse of Pesticides found that many caused negative reactions in laboratory animals. Such negative effects included kidney and liver damage, cancer, and neurological and reproductive problems.

These implications of these findings are far-reaching. Given the variety of harmful effects attributed to those pesticides tested, one must pause and consider whether it is wise to continue their use in the nation’s schools, where children will be constantly exposed to them. Activists have lobbied for the elimination of such use with a degree of success, and recent findings, if supported by further analysis and confirmation, may help further the cause. A long term solution or alternative, however, remains elusive.

In the short run, however, there may be some measures that can be taken to mitigate the harmful effects of dangerous pesticides. The American Medical Association’s Council on Scientific Affairs concluded in a 1997 report that given the "particular uncertainty.., regarding the long-term health effects of low-dose pesticide exposures," it is "prudent" for adults and children to limit their exposure and to "consider the use of the least toxic chemical pesticides or non-chemical alternatives. \

The author mentions the exaggerated effects of chemicals on children in paragraph 2 to()

A. prove that pesticides are dangerous to all humans

B. show that children are more susceptible to many kinds of dangers

C. suggest a solution to the problem of pesticides

D. identify one group that pesticides hurt in particular

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法国历史学家布罗代尔说:"一种文明的历史,就是对古代材料中那些对今天仍然行之有效的东西的探索。它有待解决的问题不在于要告诉人们关于希腊文明或中世纪中国我们所知的一切--而是要告诉人们在西欧或现代中国以前的时代与今天仍旧相关的东西。"在这里,布罗代尔强调的是()。

A.史学是当代人的历史认识

B.以探索的精神研究历史

C.史学无须穷尽人类文明的历史

D.从文明传承的角度阐释历史

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地壳中的各种元素在各种地质作用下,由一种或几种元素结合而成的()或()叫做矿物。

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