English verb conjugation
COULD CREASE

Regular verb: crease - creased - creased

Affirmation

Simple form	V-ing form
I could crease you could crease he could crease we could crease you could crease they could crease	I could be creasing you could be creasing he could be creasing we could be creasing you could be creasing they could be creasing
Perfect	V-ing perfect
I could have creased you could have creased he could have creased we could have creased you could have creased they could have creased	I could have been creasing you could have been creasing he could have been creasing we could have been creasing you could have been creasing they could have been creasing

Negation

Simple form	V-ing form
I couldn't crease you couldn't crease he couldn't crease we couldn't crease you couldn't crease they couldn't crease	I couldn't be creasing you couldn't be creasing he couldn't be creasing we couldn't be creasing you couldn't be creasing they couldn't be creasing
Perfect	V-ing perfect
I couldn't have creased you couldn't have creased he couldn't have creased we couldn't have creased you couldn't have creased they couldn't have creased	I couldn't have been creasing you couldn't have been creasing he couldn't have been creasing we couldn't have been creasing you couldn't have been creasing they couldn't have been creasing

Interrogative form

Simple form	V-ing form
could I crease? could you crease? could he crease? could we crease? could you crease? could they crease?	could I be creasing? could you be creasing? could he be creasing? could we be creasing? could you be creasing? could they be creasing?
Perfect	V-ing perfect
could I have creased? could you have creased? could he have creased? could we have creased? could you have creased? could they have creased?	could I have been creasing? could you have been creasing? could he have been creasing? could we have been creasing? could you have been creasing? could they have been creasing?

Interro-negative form

Simple form	V-ing form
couldn't I crease? couldn't you crease? couldn't he crease? couldn't we crease? couldn't you crease? couldn't they crease?	couldn't I be creasing? couldn't you be creasing? couldn't he be creasing? couldn't we be creasing? couldn't you be creasing? couldn't they be creasing?
Perfect	V-ing perfect
couldn't I have creased? couldn't you have creased? couldn't he have creased? couldn't we have creased? couldn't you have creased? couldn't they have creased?	couldn't I have been creasing? couldn't you have been creasing? couldn't he have been creasing? couldn't we have been creasing? couldn't you have been creasing? couldn't they have been creasing?