The subjunctive mood is the base form of the verb (without -s, without do) used in formal style after verbs and expressions of demand, suggestion, or necessity: suggest, recommend, insist, demand, propose, it is essential/vital/important that.
suggest / insist / demand / it is essential + that + subject + base form (be, go, not be)
- The doctor recommended that he stop smoking. – The doctor recommended that he quit smoking (not: stops).
- It is essential that every student be present. – It is necessary that every student be present.
- She insisted that he not tell anyone. – She insisted that he not tell anyone.
In British English, a common version is with should: The doctor recommended that he should stop smoking. Established phrases with the subjunctive mood: God save the King, be that as it may, so be it, if need be.