§482. Tenses of the Subjunctive

The tenses of the Subjunctive in Dependent Clauses follow special rules for the Sequence of Tenses.

With reference to these rules all tenses when used in independent clauses are divided into two classes,—Primary and Secondary.

• PRIMARY.—The Primary Tenses include all forms that express present or futuretime. These are the Present, Future, and Future Perfect Indicative, the Present and Perfect Subjunctive, and the Present and Future Imperative.
• SECONDARY.—The Secondary Tenses include all forms that refer to past time. These are the Imperfect, Perfect, and Pluperfect Indicative, the Imperfect and Pluperfect Subjunctive, and the Historical Infinitive.

The Perfect Definite is sometimes treated as primary (see § 485. a).

For the Historical Present, see § 485. e; for the Imperfect Subjunctive in Apodosis, see § 485. h.