[1737.] (c.) Action subsequent to a main present is expressed by the future participle with a present form of sum, to a main future or virtual future by the future participle with a future form of sum, and to a main secondary tense by the future participle with an imperfect form of sum: as,
decem diēs sunt ante lūdōs, quōs Cn. Pompēius factūrus est, V. a. pr. 31, there are ten days before the shows which Pompey is to manage. attentōs faciēmus, sī dēmōnstrābimus ea, quae dictūrī erimus, magna esse, Inv. 1, 23, we shall make people attentive if we show that what we are going to say is important. rēx, quia nōn interfutūrus nāvālī certāminī erat, Magnēsiam concessit, L. 36, 43, 9, as the king was not to have a hand in the action at sea, he moved off to Magnesia.
[1738.] II. A subordinate indicative tense is said to be Independent when it simply expresses time of its own, without any close relation to the time of the main action.
Such independent tenses may denote general present action: as, ībam forte viā sacrā, sīcut meus est mōs, H. S. 1, 9, 1, in Sacred Street, as is my wont, I happened to be promenading (relatively, erat mōs, [1735]). nōn mē appellābis, sī sapis, Pl. Most. 515, you won’t address me, if you have sense (relatively, sī sapiēs, [1735]). Or past action, either continuous, completed, or indefinite: as, ut mōs fuit Bī̆thȳniae rēgibus, lectīcā ferēbātur, V. 5, 27, he regularly rode in a litter, as was the practice of the despots of Bithynia; here fuit denotes action simply as past, without further definition of time ([1603]), whereas erat, relative to the time of ferēbātur, would imply which was then the practice ([1595]).
[1739.] With dum, in the time while, an independent present is used: see [1995]. With postquam, &c., after, an independent perfect is used of a single action; see [1925].
[THE TENSES OF THE SUBJUNCTIVE.]
[1740.] Subordinate subjunctive sentences were originally independent coordinate sentences, in the tense required to express the thought. By degrees the subordinate sentence blended closely with the main sentence, and the combination of the two was regarded as one whole.
[1741.] I. The time of the subordinate subjunctive is usually Relative, that is either contemporaneous, antecedent, or subsequent, in relation to that of the main action.
[1742.] Action contemporaneous with the main action is expressed by a present or imperfect subjunctive. Action antecedent is expressed by a perfect or a pluperfect subjunctive. Action subsequent is expressed by the future participle with a form of sim or of essem.