饮用水是指什么?
参考答案:
指由集中式供水单位直接供给居民作为饮用和生活的水,该水的水质必须确保居民终生饮用安全。
There are a great number of words in the English language ______________ on colors.
A. based B. base C basing D. is based
测量设备的准确误差率小于或等于()为可以接受。
A.5%
B.6%
C.7%