酸雨观测使用的纯水通常为蒸馏水、去离子水和过滤水。
参考答案:错
If you want to keep fit, you can't eat ______ food like this. [ ]
A. much too
B. too much
C. too many
D. many too
价格是市场营销组合因素中十分敏感而又难以控制的因素。( )