Portuguese/Present subjunctive tense irregular verbs

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Most verbs which are irregular in the present tense can be made into the present subjunctive by removing the "o" from the first person present indicative

FAZER
Eu faço (present indicative) - faç

And then adding the appropriate endings:

FAZER (present subjunctive)
Eu faça
Tu faças
Ele faça
Nós façamos
Vós façais
Eles façam

However, there are some exceptions. The following verbs have irregular stems. The endings, however, are regular.

SER (to be)- eu seja

ESTAR (to be)- eu esteja

HAVER (to exist)- eu haja

SABER (to know)- eu saiba

QUERER (to will)- eu queira

The following verbs are completely irregular.

DAR (to give)
Eu dê
Tu dês
Ele dê
Nós dêmos
Vós deis
Eles dêem

And also

IR (to go)
Eu vá
Tu vás
Ele vá
Nós vamos
Vós vades
Eles vão