could catalyse
Regular verb: catalyse - catalysed- catalysed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could catalyse
you could catalyse
she could catalyse
we could catalyse
you could catalyse
they could catalyse 	I could be catalysing
you could be catalysing
she could be catalysing
we could be catalysing
you could be catalysing
they could be catalysing	I could have catalysed
you could have catalysed
she could have catalysed
we could have catalysed
you could have catalysed
they could have catalysed	I could have been catalysing
you could have been catalysing
she could have been catalysing
we could have been catalysing
you could have been catalysing
they could have been catalysing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not catalyse
you could not catalyse
she could not catalyse
we could not catalyse
you could not catalyse
they could not catalyse 	I could not be catalysing
you could not be catalysing
she could not be catalysing
we could not be catalysing
you could not be catalysing
they could not be catalysing	I could not have catalysed
you could not have catalysed
she could not have catalysed
we could not have catalysed
you could not have catalysed
they could not have catalysed	I could not have been catalysing
you could not have been catalysing
she could not have been catalysing
we could not have been catalysing
you could not have been catalysing
they could not have been catalysing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I catalyse?
could you catalyse?
could she catalyse?
could we catalyse?
could you catalyse?
could they catalyse? 	could I be catalysing?
could you be catalysing?
could she be catalysing?
could we be catalysing?
could you be catalysing?
could they be catalysing? 	could I have catalysed?
could you have catalysed?
could she have catalysed?
could we have catalysed?
could you have catalysed?
could they have catalysed? 	could I have been catalysing?
could you have been catalysing?
could she have been catalysing?
could we have been catalysing?
could you have been catalysing?
could they have been catalysing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not catalyse?
could you not catalyse?
could she not catalyse?
could we not catalyse?
could you not catalyse?
could they not catalyse? 	could I not be catalysing?
could you not be catalysing?
could she not be catalysing?
could we not be catalysing?
could you not be catalysing?
could they not be catalysing? 	could I not have catalysed?
could you not have catalysed?
could she not have catalysed?
could we not have catalysed?
could you not have catalysed?
could they not have catalysed? 	could I not have been catalysing?
could you not have been catalysing?
could she not have been catalysing?
could we not have been catalysing?
could you not have been catalysing?
could they not have been catalysing?