辐射防护标准中的限值有哪几类？简述它们的基本概念。

1850年，马克思看到一台电力机车模型后，就曾预言：“蒸汽大王在前一个世纪中翻转了整个世界，现在它的统治已到末 日，另外一个更大的无比的革命力量——电，将取而代之。”对此理解不正确的是[ ]

A．一百多年来的历史充分证明了马克思预言的正确性

B．当时实际可用的发电机的问世是此预言的基础

C．电灯、电话、电影放映机的涌现印证了这一预言

D．电气技术比蒸汽技术将提供更为强大便捷而又廉价的动力

当太阳移动时，蜥蜴的部分肋骨就延长，使身体扁平并与太阳成直角。这种特殊性是由什么决定的？（）

A．向光性

B．应激性

C．遗传性

D．适应性

因国家建设需要，将已设定抵押权的房地产列入拆迁房屋的，应当及时书面通知（）。

A.抵押人或抵押权人

B.债务人

C.抵押人

D.抵押权人

某上市公司20×7年财务会计报告批准报出日为20×8年4月10日。公司在20×8年1月1日至4月10日发生的下列事项中，属于资产负债表日后调整事项的是( )。

A．公司在一起历时半年的诉讼中败诉，支付赔偿金50万元，公司在上年末已确认预计负债30万元

B．因遭受水灾上年购入的存货发生毁损100万元

C．公司董事会提出20×7年度利润分配方案为每10股送3股股票股利

D．公司支付20×7年度财务报告审计费40万元

Almost every day we see something in the papers about the latest exciting developments in the space race. Photographs are regularly flashed to the earth from thousands and even millions of miles away. They are printed in our newspapers and shown on our television screens as a visible proof of the man’s newest achievements. The photographs neatly sum up the results of these massive efforts to ’ conquer space’ and at the same time they exposed the absurdity of the undertaking. All we can see is an indistinguishable blob that is supposed to represent a planet seen from several thousand miles away. We are going to end up with a little moon-dust and a few stones which will be put behind glass in some museum. (41)__________

(42)__________It is just an extension of the race for power on earth. Only the wealthiest nations can compete and they do so in the name of pure scientific research. But in reality, all they are interested in is power and prestige. They want to impress us, their spectators, with a magnificent show of strength. Man has played the power game ever since he appeared on earth. Now he is playing it as it has never been played before. The space race is just another aspect of the age-old argument that "might is right".

(43)__________But what has the space race done to relieve the suffering of the earth’s starving millions In what way has it raised the standard of living of any one of us As far as the layman is concerned, the practical results of all this expenditure of money and efforts are negligible. Thanks to space research, we can now see television pictures transmitted live halfway across the globe and the housewife can use non-stick frying pans in the kitchen. The whole thing becomes utterly absurd when you think that no matter what problems man overcomes, it is unlikely that he will ever be able to travel even to the nearest star.

(44)__________For the first time in his history, man has the overwhelming technological resources to combat human suffering, yet he squanders them on meaningless pursuits.

(45)__________Individuals with limited budgets usually get their priorities right; they provide themselves with necessities before trying to obtain luxuries. Why can’t great nations act in the same sensible way Let us put our house in order first and let space look after itself.

44（）

A.An increasing number of people even begin to picture a space travel in recent years.

B.Poverty, hunger, disease and war are man’s greatest enemies and the world would be an infinitely better place if the powerful nations devoted half as much money and effort to these problems as they do to the space race.

C.The space race is not simply the objective search for knowledge though it is often made out to be.

D.On the other hand, people benefit dramatically from the development of science and technology.

E.This is hardly value for money when you think that our own earth can provide countless sights that are infinitely more exciting and spectacular.

F.We are often told that technological know-how, acquired in attempting to get us into orbit, will be utilized to make better on earth.

G.If a man deprived himself and his family of food in order to buy and run a car, we would consider him mad.