The earthquake in Japan was so violent___cause a series of explosions of the nuclear reactions.

题目

The earthquake in Japan was so violent___cause a series of explosions of the nuclear reactions.
A.to B that c as to D as that

答案

so as to
以便；以致
因为后面并不是从句,是个不定式结果状语.
如果改成:so violent () it cause .
这就是从句了,就应该用:B that