【求助帖】

pata1988

1.Most of the world's supply of uranium currently comes from mines.  It is possible to extract uranium from seawater, but the cost of doing so is greater than the price that uranium fetches on the world market.  Therefore, until the cost of extracting uranium from seawater can somehow be reduced, this method of obtaining uranium is unlikely to be commercially viable.
Which of the following would it be most useful to determine in evaluating the argument?
(A) Whether the uranium in deposits on land is rapidly being depleted
(B) Whether most uranium is used near where it is mined
(C) Whether there are any technological advances that show promise of reducing the cost of extracting uranium from seawater
(D) Whether the total amount of uranium in seawater is significantly greater than the total amount of uranium on land
(E) Whether uranium can be extracted from freshwater at a cost similar to the cost of extracting it from seawater
答案给的是A，why not B？
2.Which of the following most logically completes the argument?
United States manufacturers currently produce most of the world's solar-power generators--most of which are exported to Europe.  However, European manufacturers are emerging and probably will ultimately capture much of the European market.  The United States government is funding initiatives intended to encourage use of solar power within the United States.  If these initiatives succeed in increasing the demand for solar-power generators in the United States, United States manufacturers will probably maintain significant production levels, since __________.
(A) some United States manufacturers have been substantially increasing their output over the last several years
(B) the efficiency of solar-power generators in converting energy from the Sun into electric power is not improving as fast as it once did
(C) just as European manufacturers enjoy certain competitive advantages in Europe, so do United States manufacturers in the United States
(D) European governments are currently undertaking initiatives to stimulate the use of solar power within Europe
(E) the current market for solar-power generators in the United States is very limited
答案给的C，why not E？

agnesliu

1.结论是until the cost of extracting uranium from seawater can somehow be reduced, this method of obtaining uranium is unlikely to be commercially viable.
意思是说，从seawater中提取U的成本不降低，这个方法就不可行
那么削弱因素是什么呢？应该是除成本外的其它因素的影响
A正好说明了无论成本降不降，如果land不可行，只能seawater了
B使用地跟开采地近不近，还是围绕着成本因素啊~不能削弱

agnesliu

2.European厂开始制造太阳能了就能占领E市场，US厂退回US就能守住US市场，因为……C很直接啊
E选项混淆性还蛮强的，乍一看很有道理，只有US市场未充分开发，US退回去才能维持销售啊。可是不如C，如果只是US市场不饱和这一条件，既然E能把US赶出E，那么E也有可能占领US

pata1988

学习了~从你的讲解中有所觉悟！感谢！！