The Gulches is an area of volcanic rock that is gashed by many channels that lead downhill from the site of a prehistoric glacier to a river. The channels clearly were cut by running water. It was once accepted as fact that the cutting occurred gradually, as the glacier melted. But one geologist theorized that the channels were cut in a short time by an enormous flood. The channels do show physical evidence of having been formed quickly, but the flood theory was originally rejected because scientists knew of no natural process that could melt so much ice so quickly. Paradoxically, today the scientific community accepts the flood theory even though scientists still do not know of a process that can melt so much ice so quickly.
17. Which one of the following, if true, most helps to resolve the apparent paradox in the passage?
(A) Ripples, which indicate that the channels were cut by water, have been discovered in the floors of the channels.
(B) The Gulches is known to be similar in certain respects to many other volcanic rock formations.
(C) More than one glacier was present in the area during prehistoric times.
(D) Volcanic rock is more easily cut by water than are other forms of rock.（E）
(E) Scientists now believe that the prehistoric glacier dammed a source of water, created a huge lake in the process, and then retreated.
答案是E。 为甚么E解释了这个paradox?
| 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2004-8-2 23:25:00
楼主
