The subjunctive is formed by dropping the -ons ending from the first person plural of the present indicative and adding the endings:
Most irregularities are perfectly regular.
For verbs ending in -yer (payer, envoyer,
etc) the vowel changes are the same as those for the present indicative.
Verbs that change -e to -è in the
singular and the third person plural forms (acheter, etc) in the
present indicative, also change -e to -è
in the subjunctive.
Verbs that change -é to -è
in the singular and the third person plural forms (espérer,
préférer, etc) in the present indicative, also change
-é to -è in the subjunctive.
The base changes are also the same for mourir, recevoir
(décevoir, percevoir, etc), devoir, boire,
croire, voir in the present indicative and the present
subjunctive.
Uses of The Subjunctive
The Past Subjunctive is formed by adding the past participle
to the auxiliary verb in the subjunctive: item 11.
Most verbs, including avoir (c'est le meilleur travail que
j'aie eu depuis longtemps) and être (Quelle chance
qu'ils aient été là!) are conjugated with avoir.
That is to say: as usual, you only need to know two verbs.
As with the Passé Composé, reflexive verbs are conjugated
with être (Les commerçants acceptent
l'argent liquide en attendant que l'usage d'une carte bancaire se soit banalisé).
Grammar books never forget to warn you: such and such verbs
or conjunctions must be followed by ne. We call it: the
ne explétif. It has no negative value and is disappearing
from spoken language and not without reason. Compare:
Elle a peur qu'il ne meure: the ne explétif
has no negative value and the sentence means: she is afraid that he will
die.
Elle a peur qu'il ne meure pas: ne ... pas is
the negative and the sentence means: she is afraid that he won't die.
It is easy to imagine that misunderstanding may happen.