2004.10 section D No. 17：Climatologists believe they know why Earth has undergone a regular sequence of ice ages beginning around 800,000 years ago. Calculations show that Earth's orbit around the Sun has fluctuations that coincide with the ice-age cycles. The climatologists hypothesize that when the fluctuations occur, Earth passes through clouds of cosmic dust that enters the atmosphere; the cosmic dust thereby dims the Sun, resulting in an ice age. They concede, however, that though cosmic dust clouds are common, the clouds would have to be particularly dense in order to have this effect.
Each of the following, if true, would lend support to the climatologists' hypothesis EXCEPT:
A. Earth did not pass through clouds of cosmic dust earlier than 800,000 years ago.
B. Two large asteroids collided 800,000 years ago, producing a tremendous amount of dense cosmic dust that continues to orbit the Sun.
C. Earth's average temperature drops slightly shortly after volcanic eruptions spew large amounts of dust into Earth's atmosphere.
D. Large bits of cosmic rock periodically enter Earth's atmosphere, raising large amounts of dust from Earth's surface.
E. Rare trace elements known to be prevalent in cosmic debris have been discovered in layers of sediment whose ages correspond very closely to the occurrence of ice ages.
以前我理解的是，一种trace elements (the elements that are known to be prevalent in cosmic debris) 很少被发现 （this kind of elements correspond to the occurrence of ice age）。这种理解是削弱原文的，好像是答案。
但其实 E 选项的正确理解应该是， 很稀有的trace elements被发现了，这种elements correspond to the occurrence of ice age。这种理解就是支持原文的。
