The SUBJUNCTIVE MOOD in English
The subjunctive mood is widely used in Spanish but much less so in English. Here are some useful comments about the English subjunctive which I found in various sites online.
Structure of the Subjunctive
The structure of the subjunctive is extremely simple. For all verbs except the past tense of be, the subjunctive is the same as the bare infinitive (infinitive without "to"):
TO BE (present subjunctive):
I be
you be
he, she, it be
we be
you be
they be
TO BE (past subjunctive):
I were
you were
he, she, it were
we were
you were
they were
ALL OTHER VERBS, using TO WORK as a model:
I work
you work
he, she, it work
we work
you work
they work
You can form subjunctives in English with WERE, HAD, IF, and AS THOUGH. It also follows WISH and SUPPOSE.
Examples:
If Roger were an honorable spy, he would not reveal the secret.
If I were president, I would ask the colony to secede.
Eggworthy hurtled through the air as though a giant metal device were intent on scrambling him.
If Lola had known (or, Had Lola known...) about the atomic secret, she would not have revealed it.
His Majesty further insists that his wedding planner remain in the palace.
These sites have good explanations and further examples:
http://www.englishpage.com/minitutorials/subjunctive.html
and
https://www.englishclub.com/grammar/verbs-subjunctive.htm