标题: prep 135 [打印本页] 作者: wang1502 时间: 2011-1-2 04:45 标题: prep 135 135. Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period. A. which, causing plant and animal extinctions, marks B. which caused the plant and animal extinctions marking C. and causing plant and animal extinctions that mark D. an event that caused plant and animal extinctions, and it marks E. an event that caused the plant and animal extinctions that mark