题干
30. 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
答案(点此获取答案解析）
C
A：so useful a way
B：as a useful way
C：as useful a way
D：such useful way
溶液反应的化学方程式为： 
．则下列说法错误的是( )