tap
n. 水龙头;龙头;旋塞;轻击;轻拍;轻敲;轻扣;电话窃听
v. 轻敲;轻拍;轻叩;(用…)轻轻叩击

【例句】
You can ask for a chemical analysis of your tap water.
你可以要求给你的自来水做化学分析。

When water is used this must be distilled water or spring water; never tap water.
用水的时候必须是蒸馏水或泉水，绝不能用自来水。