There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than ten times as much energy is generated through wind power now than it was in 1990.
我好像做过这个题,然后答案好像,好像啊,说the case in 1990和前面now发生的事情形成比较。就是对于energy通过风能产生这件事1990年和现在的情况进行个对比 然后D选项,是不是it指代不清啊。不确定,我觉得GMAT语法里面it指代问题总会出毛病,所以不是那种指代极为明显的,还是再找找其他有木有更好的答案