比率

谈到比例和比率，我们最大的障碍是很容易读错题意。请注意以下三项的表达方式：

What percent of A is B? 这个问题问的是B/A。

What is the ratio of A to B? 这个问题问的是A:B。

A is three times as many as B；There is three times as many A as B. 这两句话的意思都是A = 3B

A is three times more than B. 这句话的意思是A = 4B