(a.) Protasis and apodosis both denoting present action; this is the
usual application: #sī intus esset, ēvocārem#, Pl. _Ps._ 640, _I should
call him out, if he were in_. #is iam prīdem est mortuus. sī vīveret,
verba eius audīrētis#, _RC._ 42, _that person has long been dead; if he
were alive, you would hear his evidence_. #adnuere tē videō; prōferrem
librōs, sī negārēs#, _DN._ 1, 113, _I see you nod assent; I should bring
out the books, if you maintained the opposite_. #sī L. Mummius aliquem
istōrum vidēret Corinthium cupidissimē trāctantem, utrum illum cīvem
excellentem, an ātriēnsem dīligentem putāret?# _Par._ 38, _if Mummius
should see one of your connoisseurs nursing a piece of Corinthian, and
going into perfect ecstasies over it, what would he think? that the man
was a model citizen or a thoroughly competent indoor-man?_ #quod sī
semper optima tenēre possēmus, haud sānē cōnsiliō multum egērēmus#,
_OP._ 89, _now if we could always be in possession of what is best, we
should not ever stand in any special need of reasoning_.
(b.) Protasis and apodosis both denoting past action: #haec sī neque ego
neque tū fēcimus, nōn siit egestās facere nōs; nam sī esset unde id
fīeret, facerēmus; et tū illum tuom, sī essēs homō, sinerēs nunc
facere#, T. _Ad._ 103, _if neither you nor I have acted thus, ’twas
poverty that stinted us; for if we’d had the means, we should have done
so too; and you would let that boy of yours, if you were human, do it
now_. Here #esset# refers to past time, #essēs# to present. #num igitur
eum, sī tum essēs, temerārium cīvem putārēs?# _Ph._ 8, 14, _would you
therefore have thought him, if you had lived then, a hotheaded citizen?_
#sī ūniversa prōvincia loquī posset, hāc vōce ūterētur; quoniam id nōn
poterat, hārum rērum āctōrem ipsa dēlēgit#, _Caecil._ 19, _if the
collective province could have spoken, she would have used these words;
but since she could not, she chose a manager for the case herself_.