Add some salt to the boiled water: drinking it after exercise can replenish the lost salt.

Boiled water with some sugar: people with hypoglycemia can drink a little.

Boiled water with vinegar: I've never drunk it like this. ...

Add some vinegar and sugar to boiling water: it's good for your skin. Eat an apple before drinking.

Boiled water with some salt and sugar: it was given to us by adults. It tastes a little strange, but drinking it after exercise can supplement the lost salt and regulate blood pressure.