Answer:
Es necesario que tomes mucha agua.
Explanation:
Es necesario que tomes mucha agua. In English this means: It's necessary that you drink a lot of water. The verb tomar is conjugated in the subjunctive as it is either a recommendation or an order, that's why it is also called imperative (as well as subjunctive). It can be used as well to indicate a probability. For example: es posible que mañana ella tome mucha agua.
