他使用了一种特殊的清洁液来去除顽固污渍。

He used a special cleaning ___fluid to remove the stubborn stain.

医生建议发烧时要大量饮水。

Doctors advise drinking plenty of ___fluids when you have a fever.

运动期间，补充流失的水分以避免脱水至关重要。

During exercise, it's crucial to replace lost ___fluid to avoid dehydration.