The Royal Commission on Environmental Po

题型:阅读理解

问题:

The Royal Commission on Environmental Pollution has just published a report on new materials and has looked at the case of nanotechnology(纳米技术), which describes the science of the very small. Nanotechnology covers those man-made materials or objects that are about a thousand times smaller than the microtechnology(微电子技术)we use, such as the silicon chips of computers.

Nanotechnology gets its name from the nanometer, which is a billionth of a meter. There are about 600 consumer products already on the market that use nanotechnology. Nanomedicine is also being developed to fight cancer and other fatal diseases.

The Royal Commission found no evidence of harm to health or the environment from nanomaterials, but this “absence of evidence” is not being taken as “evidence of absence”. In other words, just because there are no apparent problems, this is not to say that here is no risk now or in the future. The commission is concerned about the pace at which we are inventing and adopting new nanomaterials, which could result in future problems that we are ill-equipped to understand or even find with current testing methods.

One of the problems about nanotechnology is that when we make something very small out of a well known material, we may actually change the functionality of that material even if the chemical composition remains the same. Indeed, it is not the particle(颗粒)size that should concern us, but its functionality. Take gold, for example, which is a famously inert (惰性) substance, and valuable because of it. It doesn’t rust or corrode because it doesn’t interact with water or oxygen. However, a particle of gold that is between 2 and 5 nanometers in diameter becomes highly reactive. This is not due to a change in chemical composition, but because of a change in the physical size of the gold particles. How can a change in size result in a change of function? One reason is to do with surface area. Nanoparticles have relatively a much bigger surface area. It is like comparing the surface area of a basketball with the total surface area of many pea-sized balls with the same weight of the single basketball. The pea-sized balls have a surface area many hundreds, indeed thousands of times bigger than the basketball, and this allows them to interact more easily with the environment. It is this increased interactivity that changes their functionality—and makes them potentially more dangerous to health or the environment.

小题1:Why does the writer mention microtechnology in the first paragraph?

A.to introduce the topic of nanotechnology

B.to help us better understand nanotechnology

C.to help us know more about microtechnology

D.to compare microtechnology with nanotechnology小题2:The example of the “gold” in the last paragraph is intended to show that_________.

A.gold is valuable because it is an inert substance

B.an inert substance like gold doesn’t interact with water or oxygen

C.the function of gold is steady because it is an inert substance

D.the function of gold changes when made into something very small小题3:Which process explains that there might be risks in nanotechnology?

A.expand surface area →increase interactivity → change functionality→cause possible dangers

B.expand surface area → change functionality → increase interactivity →cause possible dangers

C.increase interactivity → expand surface area → change functionality→cause possible dangers

D.increase interactivity → change functionality → expand surface area→cause possible dangers小题4:What does the passage mainly focus on?

A.the introduction of nanotechnology and its wide use

B.the present use of nanotechnology and its future

C.the potential danger nanotechnology may bring us

D.the proposal to stop nanotechnology due to the potential danger

考点:科教类阅读
题型:阅读理解

我国幅员辽阔,自然环境复杂多样,形成了各具特色的地理区域。读“中国四大地理分区图” 。回答下列问题。(7分)

(1)自然环境对居民有较大的影响,下列居民属于A地区的是_________(1分)

(2)B地区最突出的自然地理特征是_________________。(1分)

(3)现在通过管道从A地区调往C地区、D地区的能源是__________。C地区的南水北调东线工程是将___________流域丰富的水资源调入华北、西北地区(2分)

(4)南京和那曲两地纬度大致相同,但7月份南京的平均气温为28.8℃,而那曲只有8.8℃,据图分析其气温差异的主要影响因素是__________________。(1分)

题型:阅读理解

50%左右的恶性肿瘤发病与食物有关。

题型:阅读理解

患哪些疾病的人员不得从事食品工作?

题型:阅读理解

当收益率向上倾斜,并且投资人确信收益率曲线继续保持上升的趋势,投资者会购买比要求的期限短的股票。( )

题型:阅读理解

顶回法压井时要求的泵速受以下哪些井况因素的影响()。

A、地层的渗透率

B、完井方式和井下工具

C、井内完井/修井液的类型

D、溢流的类型

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