请教两道CR题~！

塔罗牌

82.(33511-!-item-!-188;#058&007598)Technological improvements and reduced equipment costs have made converting solar energy directly into electricity far more cost-efficient in the last decade.However, the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) is unchanged at thirty-five dollars.

Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased its threshold of economic viability?

A. The cost of oil has fallen dramatically.

B. The reduction in the cost of solar-power equipment has occurred despite increased raw material costs for that equipment.

C. Technological changes have increased the efficiency of oil-fired power plants.

D. Most electricity is generated by coal-fired or nuclear, rather than oil-fired, power plants.

E. When the price of oil increases, reserves of oil not previously worth exploiting become economically viable.

答案 C
括号里面那句话我读不懂~估计对解题有帮助的。这题我反复看了3遍 还是没弄明白~

shirryzhan

The mistake you made is because that you didn’t get what it means.

The threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants)--- means:The oil-fired power should have been more economical than solar power, but only if the oil rises to $35, the solar power could be more economical than oil power.



So we can tell, if the cost of solar power reduces, which means solar power is more economically viable, the threshold of economic viability should be lower, maybe to $30, because oil price doesn’t need to make so much sacrifice for solar power’s success. However, the threshold is still $35, it means that the oil power at the same time also gets more efficient. In a conclusion, oil price still need to make such a big sacrifice - % 35, to help keep solar power's economic viability

So lets think how to make oil power also more economical?

C is the right choice. The technology for oil-fired power gets efficient, so the oil power gets cheaper.

A is incorrect. The price of oil decreases dramatically. 'we are thinking about a potential threshold price for oil at which something would happen. the current price of oil -- or, indeed, the current state of absolutely anything regarding oil -- is irrelevant, so you can strike choices a/c very quickly.' (by Ron)

塔罗牌

82.(33511-!-item-!-188;#058&007598)Technological improvements and reduced equipment costs have made converting solar energy directly into electricity far more cost-efficient in the last decade.However, the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) is unchanged at thirty-five dollars.

Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased its threshold of economic viability?

A. The cost of oil has fallen dramatically.

B. The reduction in the cost of solar-power equipment has occurred despite increased raw material costs for that equipment.

C. Technological changes have increased the efficiency of oil-fired power plants.

D. Most electricity is generated by coal-fired or nuclear, rather than oil-fired, power plants.

E. When the price of oil increases, reserves of oil not previously worth exploiting become economically viable.

答案 C
括号里面那句话我读不懂~估计对解题有帮助的。这题我反复看了3遍 还是没弄明白~

-- by 会员 塔罗牌 (2011/7/25 17:52:28)

The meaning of "the threshold of economic viabilityfor solar power " is defined as "price per barrel to which oil would have to risein order for new solar power plants to be more economical than new oil-firedpower plants."
In other words, the price of oil at which the power generated by the solar power plant is cheaper that by oil-fired power plants.

This is a paradox question, for which you need to provide a clause to explain the discrepancy.  C does that.
If both the oil-fired and solar-powered plants increase their efficiency, the threshold of economic viability for solar power remains unchanged.

-- by 会员 sdcar2010 (2011/7/25 18:59:41)

我还是不怎么明白 就是说用SOLAR POWER的厂的油钱比用OIL FIRED POWER的厂的少~
那和技术变化引起效率变化 有什么关系啊？？

sdcar2010

82.(33511-!-item-!-188;#058&007598)Technological improvements and reduced equipment costs have made converting solar energy directly into electricity far more cost-efficient in the last decade.However, the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) is unchanged at thirty-five dollars.

Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased its threshold of economic viability?

A. The cost of oil has fallen dramatically.

B. The reduction in the cost of solar-power equipment has occurred despite increased raw material costs for that equipment.

C. Technological changes have increased the efficiency of oil-fired power plants.

D. Most electricity is generated by coal-fired or nuclear, rather than oil-fired, power plants.

E. When the price of oil increases, reserves of oil not previously worth exploiting become economically viable.

答案 C
括号里面那句话我读不懂~估计对解题有帮助的。这题我反复看了3遍 还是没弄明白~

-- by 会员 塔罗牌 (2011/7/25 17:52:28)

The meaning of "the threshold of economic viabilityfor solar power " is defined as "price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-firedpower plants."
In other words, the price of oil at which the power generated by the solar power plant is cheaper than that by oil-fired power plants.

This is a paradox question, for which you need to provide a clause to explain the discrepancy.  C does that.
If both the oil-fired and solar-powered plants increase their efficiency, the threshold of economic viability for solar power remains unchanged.

塔罗牌

UPUPUPUPUPUP~~~

塔罗牌

84.    (26216-!-item-!-188;#058&001794)

The general availability of high-quality electronic scanners and color printers for computers has made the counterfeiting of checks much easier.  In order to deter such counterfeiting, several banks plan to issue to their corporate customers checks that contain dots too small to be accurately duplicated by any electronic scanner currently available; when such checks are scanned and printed, the dots seem to blend together in such a way that the word “VOID” appears on the check.
A questionable assumption of the plan is that
A. in the territory served by the banks the proportion of counterfeit checks that are made using electronic scanners has remained approximately constant over the past few years
B. most counterfeiters who use electronic scanners counterfeit checks only for relatively large amounts of money
C. the smallest dots on the proposed checks cannot be distinguished visually except under strong magnification
D. most corporations served by these banks will not have to pay more for the new checks than for traditional checks
E. the size of the smallest dots that generally available electronic scanners are able to reproduce accurately will not decrease significantly in the near future

读了一遍 觉得每个选项都不相关……答案是E