求助OG12-20-114题

wintertrain

According to the passage, methods of exploring for
gold that are widely used today are based on which of
the following facts?
(A) Most of the Earth’s remaining gold deposits are still molten.
(B) Most of the Earth’s remaining gold deposits are exposed at the surface.
(C) Most of the Earth’s remaining gold deposits are buried and have no surface expression.
(D) Only one type of gold deposit warrants exploration, since the other types of gold deposits are found in regions difficult to reach.
(E) Only one type of gold deposit warrants exploration, since the other types of gold deposits are unlikely to yield concentrated quantities of gold.
官方答案中提到原文中有一句说的是：目前还未被发现的金矿大部分在地下，所以应该选C选项，即现在的方法基于金矿是埋在地下这一事实。
但此题并非inference，原文中也没有提到目前的方法跟探测地下的金矿有关联。我认为之所以地下的金矿大部分未被发现，是因为目前的方法还是应该基于人们认为金矿是在地球表面的，所以应该选B。
或者是因为B选项是一个fact而C不是，但我觉得也许人们正是觉得B是事实所以才没有发现金矿，现在思维有些混乱，求助

kronorrt

这道题其实只需要区分两个时间区间就可以了，一个是gold rushes，另外一个是methods widely used today中的today。

gold rushes（淘金热）开始于1838年，有好几轮，分布在19世纪。Most of the gold deposits discovered during the original gold rushes were exposed at the Earth’s surface and were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods. 这句话里面，淘金热时期的gold deposits是在地表的。

后面提到Although these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression.说明，虽然现在这些方法还在用，但是只是occationaly探测到地表的金矿了，已经不再适用了。

所以，现在用的method要探测的是subsurface，而非surface的金矿。