单项选择题
Once ______ water, fish can' t live.
单项选择题 Ancient people felt much()concerning the notion that the appearance of comets was inauspicious, but nevertheless exhibited () concerning the proper reaction to the phenomenon.
单项选择题 肾虚、水饮证的面色变化为()
单项选择题 目标定价法所确定的单位价格为()。