could sulfate
Regular verb: sulfate - sulfated- sulfated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could sulfate
you could sulfate
he could sulfate
we could sulfate
you could sulfate
they could sulfate 	I could be sulfating
you could be sulfating
he could be sulfating
we could be sulfating
you could be sulfating
they could be sulfating	I could have sulfated
you could have sulfated
he could have sulfated
we could have sulfated
you could have sulfated
they could have sulfated	I could have been sulfating
you could have been sulfating
he could have been sulfating
we could have been sulfating
you could have been sulfating
they could have been sulfating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't sulfate
you couldn't sulfate
he couldn't sulfate
we couldn't sulfate
you couldn't sulfate
they couldn't sulfate 	I couldn't be sulfating
you couldn't be sulfating
he couldn't be sulfating
we couldn't be sulfating
you couldn't be sulfating
they couldn't be sulfating	I couldn't have sulfated
you couldn't have sulfated
he couldn't have sulfated
we couldn't have sulfated
you couldn't have sulfated
they couldn't have sulfated	I couldn't have been sulfating
you couldn't have been sulfating
he couldn't have been sulfating
we couldn't have been sulfating
you couldn't have been sulfating
they couldn't have been sulfating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I sulfate?
could you sulfate?
could he sulfate?
could we sulfate?
could you sulfate?
could they sulfate? 	could I be sulfating?
could you be sulfating?
could he be sulfating?
could we be sulfating?
could you be sulfating?
could they be sulfating? 	could I have sulfated?
could you have sulfated?
could he have sulfated?
could we have sulfated?
could you have sulfated?
could they have sulfated? 	could I have been sulfating?
could you have been sulfating?
could he have been sulfating?
could we have been sulfating?
could you have been sulfating?
could they have been sulfating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I sulfate?
couldn't you sulfate?
couldn't he sulfate?
couldn't we sulfate?
couldn't you sulfate?
couldn't they sulfate? 	couldn't I be sulfating?
couldn't you be sulfating?
couldn't he be sulfating?
couldn't we be sulfating?
couldn't you be sulfating?
couldn't they be sulfating? 	couldn't I have sulfated?
couldn't you have sulfated?
couldn't he have sulfated?
couldn't we have sulfated?
couldn't you have sulfated?
couldn't they have sulfated? 	couldn't I have been sulfating?
couldn't you have been sulfating?
couldn't he have been sulfating?
couldn't we have been sulfating?
couldn't you have been sulfating?
couldn't they have been sulfating?