Subjunctive Mood

Subjunctive mood is the verb form that usually express the suggestion, wish, command, doubt, etc. Sometimes, it represents an imaginary situation or a condition that is opposite to the fact.
A verb is used with the same subject is different from the form of a verb in the subjunctive mood.
I was in the same class two years ago. (Without subjunctive mood)
If I were in the same class, I would perform better in the tests. (Subjunctive mood)
However, the subjunctive mood is usually used in the clauses, where a verb expresses a wish, regret, proposal, demand, etc.

More examples of Subjunctive mood:
The owner of the factory suggests that Bob work full time with this organization.
If I were the high authority, I would take better decision.
I wish I were in the city to enjoy the speed of life.
I wish I were in the same situation.

Non-subjunctive form: He cooks

Subjunctive form: I hope that he cook for us.

Rules of the Subjunctive Mood:
• In subjunctive mood, the ‘s’ and ‘es’ are not available with the verb,which is related to the third person singular (subject). It seems the present tense for everything.
• In the subjunctive mood, the ‘to be’ is written as ‘be’ in the present tense, whereas ‘were’ is used in the past tense, whatever the subject is.
• The future subjunctive is rarely used.

Verbs mostly used in the Subjunctive Mood:
Command, ask, demand, recommend, wish, suggest and others.

Adjectives mostly used in the Subjunctive Mood:
Essential, necessary, imperative, etc.