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.
语法 Sentence Correction-3881
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tomaghost 2016-06-12 10:50:19
which需要有具体的指代对象，不能用于修饰前句整句描述的事情;causing现在分词表示动作正在进行或还在延续，含义不正确。
hbhqr 2015-02-05 23:41:07
感觉causing作为插入语，which marks。。。同时修饰前面asteroid slammed into NA这件事。所以选了A
hbhqr 2015-02-05 23:46:06
忽略了which在GMAT中一般不能指代前面的整个事件，所以AB不合适。 E中注意Marks的事件指的是动植物灭绝，所以排除D
