Irregular verbs do not follow standard rules of conjugation in the different verb tenses. There are many irregular verbs in the Spanish present subjunctive:

ser (example sentences)(full conjugation)

			

				
 
				
 
				
 
			
			

				
yo
				
 sea
				
(that I may be)
			
			

				
tú
				
 seas
				
(that you may be)
			
			

				
Ud./él/ ella
				
 sea
				
(that you may be)
			
			

				
nosotros (as)
				
 seamos
				
(that we may be)
			
			

				
vosotros (as)
				
 seáis
				
(that you guys may be)
			
			

				
Uds./ellos/ ellas
				
 sean
				
(that you all/they may be)
			
		

dar (example sentences)(full conjugation)

			

				
 
				
 
				
 
			
			

				
yo
				
 dé
				
(that I may give)
			
			

				
tú
				
 des
				
(that you may give)
			
			

				
Ud./él/ ella
				
 dé
				
(that you may give)
			
			

				
nosotros (as)
				
 demos
				
(that we may give)
			
			

				
vosotros (as)
				
 deis
				
(that you guys may give)
			
			

				
Uds./ellos/ ellas
				
 den
				
(that you all/they may give)
			
		

ir (example sentences)(full conjugation)

			

				
 
				
 
				
 
			
			

				
yo
				
 vaya
				
(that I may go)
			
			

				
tú
				
 vayas
				
(that you may go)
			
			

				
Ud./él/ ella
				
 vaya
				
(that you may go)
			
			

				
nosotros (as)
				
 vayamos
				
(that we may go)
			
			

				
vosotros (as)
				
 vayáis
				
(that you guys may go)
			
			

				
Uds./ellos/ ellas
				
 vayan
				
(that you all/they may go)
			
		

Let's look at some example sentences:

¿Quiere que sea testigo?
Do you want me to be a witness?

No importa que sea de otro país.
It doesn’t matter if it's from another county.

Quiere que vayas al hospital.
He/she wants you to go to the hospital.

Es necesario que vayas.
It's necessary that you go.