English verb conjugation
COULD CATALYSE

Regular verb: catalyse - catalysed - catalysed

Affirmation

Simple form	V-ing form
I could catalyse you could catalyse he could catalyse we could catalyse you could catalyse they could catalyse	I could be catalysing you could be catalysing he could be catalysing we could be catalysing you could be catalysing they could be catalysing
Perfect	V-ing perfect
I could have catalysed you could have catalysed he 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 he 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
I couldn't catalyse you couldn't catalyse he couldn't catalyse we couldn't catalyse you couldn't catalyse they couldn't catalyse	I couldn't be catalysing you couldn't be catalysing he couldn't be catalysing we couldn't be catalysing you couldn't be catalysing they couldn't be catalysing
Perfect	V-ing perfect
I couldn't have catalysed you couldn't have catalysed he couldn't have catalysed we couldn't have catalysed you couldn't have catalysed they couldn't have catalysed	I couldn't have been catalysing you couldn't have been catalysing he couldn't have been catalysing we couldn't have been catalysing you couldn't have been catalysing they couldn't have been catalysing

Interrogative form

Simple form	V-ing form
could I catalyse? could you catalyse? could he catalyse? could we catalyse? could you catalyse? could they catalyse?	could I be catalysing? could you be catalysing? could he be catalysing? could we be catalysing? could you be catalysing? could they be catalysing?
Perfect	V-ing perfect
could I have catalysed? could you have catalysed? could he 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 he 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
couldn't I catalyse? couldn't you catalyse? couldn't he catalyse? couldn't we catalyse? couldn't you catalyse? couldn't they catalyse?	couldn't I be catalysing? couldn't you be catalysing? couldn't he be catalysing? couldn't we be catalysing? couldn't you be catalysing? couldn't they be catalysing?
Perfect	V-ing perfect
couldn't I have catalysed? couldn't you have catalysed? couldn't he have catalysed? couldn't we have catalysed? couldn't you have catalysed? couldn't they have catalysed?	couldn't I have been catalysing? couldn't you have been catalysing? couldn't he have been catalysing? couldn't we have been catalysing? couldn't you have been catalysing? couldn't they have been catalysing?