[Double Happy]

Подскажите, как правильно перевести сл. предложения из песен. Заранее спасибо.

If you ever should leave, why would I want to live? ( Если ты уйдешь/ Ушел бы / Должен уйти /Если тебе суждено уйти...)

If I should die, my soul be lost (Если я умру / умерла бы / мне суждено умереть/ должна умереть).
Где бы еще найти подробное современное правило на should/would?

[Thomas]

If you ever should leave, why would I want to live?

Если тебе когда-нибудь придётся уйти, зачем бы мне жить?

If I should die, my soul be lost

Если мне придётся умереть, моя душа пропадёт.

[Double Happy]

Спасибо, Thomas! Я также интересовался данным вопросом на одном языковом форуме, и вот что мне ответили:

"There is a distinction in English between a "real" conditional, and an "unreal" conditional. In a real conditional, the speaker presents the action as likely or certainly possible. The present tense is used in the if-clause in English, and the future tense is needed in the if-clause in Russian.
Если ты уйдешь, cтанет мне темно ... If you go away, I will be gloomy
Если ты уйдешь - как мне дальше жить ... If you go away, how will/can I go on living?

The use of a conditional or modal verb ("should") in English, reinforced further by the adverb "ever" (когда-нибудь), means that the sense of the English phrase is an unreal conditional; the speaker is speculating on something that might or might not happen, it is doubtful. Unreal conditions in Russian consist of a conditional clause and a consequence clause, both expressed with the conditional particle бы.

..If you ever should leave,)
..If you should ever leave,)
..If ever you should leave,)
..............If you ever left,) why would I want to live? Если бы ты ушёл, зачем бы мне жить? (Adverbs could be added to the first clause in Russian)
..............If ever you left,)
If you were ever to leave,)
If ever you were to leave,)

Your second example is not so clear. The rest of the immediate grammatical context is: She told me if I should die, my soul be lost, ain"t nobody"s fault but mine! There are three factors complicating the use of tenses here: (1 - and the most significant) it's black American English dialect, so the tenses do not necessarily follow the normal sequence rules; (2) the tenses are affected by the sequence of tenses in reported speech (she told me..); (3) it's not prose, it's a song, so the tense form might also be affected by the number of syllables in the words, to fit the metre.

Despite the "should", it's not really an unreal conditional, because he/she will definitely die at some point. The meaning is: If my soul is lost when I die, it will be nobody's fault but mine. So it's a real conditional, and in my opinion, it needs future tenses in Russian."

[Thomas]

Ну если два свидетеля говорят одно и то же, то значит это объективный факт