The auxiliary verbs do, does and did are followed by the bare infinitive to form negative and interrogative sentences in the past simple and present simple tenses:
The past continuous subjunctive can be used in the if-clause of a sentence in the second conditional to express an unreal action in the present which is imagined as continuous:
The past subjunctive has the same form as the past simple tense except in the case of the verb be. Traditionally, the past subjunctive form of be is were for all persons, including the first and third person singular.
