a. The Latin is much more exact in the use of the Future Perfect than the English, which commonly employs the Present Perfect instead of the Future Perfect.
b. In those verbs whose Perfect has Present force ([§ 262], A) the Future Perfect has the force of a Future; as,—
nōverō, I shall know.
Epistolary Tenses.
[265]. In letters the writer often uses tenses which are not appropriate at the time of writing, but which will be so at the time when his letter is received; he thus employs the Imperfect and the Perfect for the Present, and the Pluperfect for the Present Perfect; as,—
nihil habēbam quod scrīberem, neque enim novī quidquam audieram et ad tuās omnēs epistulās jam rescrīpseram, I have nothing to write, for I have heard no news and have already answered all your letters.
TENSES OF THE SUBJUNCTIVE.
[266]. A. In Independent sentences. See [§§ 272]-280.
B. In Dependent Sentences. In dependent sentences the tenses of the subjunctive usually conform to the so-called
Sequence of Tenses.
[267]. 1. In the Subjunctive the Present and Perfect are Principal tenses, the Imperfect and Pluperfect, Historical.