语法题.
问题描述：
语法题.
In 1911 the Great Blue Norther,a massive storm in the midwestern United States,（it caused） temperatures in some cites to drop more than 60 degrees in a single day.
为什么用caused 不用causing.
答
In 1911 (时间状语）the Great Blue Norther（句子主语）,a massive storm in the midwestern United States,（主语同位语） caused （句子谓语）temperatures in some cites to drop more than 60 degrees in a sin...