Exercise is as any other to lose unwanted weight.
A. so useful a way
B. as a useful way
C. as useful a way
D. such useful way
网友回答
A. so useful a way
B. as a useful way
(答案→)C. as useful a way
D. such useful way
解析：“锻炼和其他减肥方法一样是一个有用的方法。”such a +形容词+名词，so/as+形容词+a+名词，so只用于否定句，所以答案C。