概括大意与完成句子
Volcanoes were more destructive in ancient history. Not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease. Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do.
Older eruptions were more devastating _____________.
A、than more recent ones
B、the killing efficiency for older eruptions
C、has been known to us all
D、Wignalls calculations as acceptable
【正确答案】 A
【答案解析】 仅从语法的角度讲就可以判断选择A。more devastating用了比较级，通常比较级是有比较对象的，而比较对象由than连接，另外A选项填入空后与本段文字的第一句话表达相同的意思，因此选择A。
