English verb conjugation
COULD VITRIFY

Regular verb: vitrify - vitrified - vitrified

Affirmation

Simple form	V-ing form
I could vitrify you could vitrify he could vitrify we could vitrify you could vitrify they could vitrify	I could be vitrifying you could be vitrifying he could be vitrifying we could be vitrifying you could be vitrifying they could be vitrifying
Perfect	V-ing perfect
I could have vitrified you could have vitrified he could have vitrified we could have vitrified you could have vitrified they could have vitrified	I could have been vitrifying you could have been vitrifying he could have been vitrifying we could have been vitrifying you could have been vitrifying they could have been vitrifying

Negation

Simple form	V-ing form
I couldn't vitrify you couldn't vitrify he couldn't vitrify we couldn't vitrify you couldn't vitrify they couldn't vitrify	I couldn't be vitrifying you couldn't be vitrifying he couldn't be vitrifying we couldn't be vitrifying you couldn't be vitrifying they couldn't be vitrifying
Perfect	V-ing perfect
I couldn't have vitrified you couldn't have vitrified he couldn't have vitrified we couldn't have vitrified you couldn't have vitrified they couldn't have vitrified	I couldn't have been vitrifying you couldn't have been vitrifying he couldn't have been vitrifying we couldn't have been vitrifying you couldn't have been vitrifying they couldn't have been vitrifying

Interrogative form

Simple form	V-ing form
could I vitrify? could you vitrify? could he vitrify? could we vitrify? could you vitrify? could they vitrify?	could I be vitrifying? could you be vitrifying? could he be vitrifying? could we be vitrifying? could you be vitrifying? could they be vitrifying?
Perfect	V-ing perfect
could I have vitrified? could you have vitrified? could he have vitrified? could we have vitrified? could you have vitrified? could they have vitrified?	could I have been vitrifying? could you have been vitrifying? could he have been vitrifying? could we have been vitrifying? could you have been vitrifying? could they have been vitrifying?

Interro-negative form

Simple form	V-ing form
couldn't I vitrify? couldn't you vitrify? couldn't he vitrify? couldn't we vitrify? couldn't you vitrify? couldn't they vitrify?	couldn't I be vitrifying? couldn't you be vitrifying? couldn't he be vitrifying? couldn't we be vitrifying? couldn't you be vitrifying? couldn't they be vitrifying?
Perfect	V-ing perfect
couldn't I have vitrified? couldn't you have vitrified? couldn't he have vitrified? couldn't we have vitrified? couldn't you have vitrified? couldn't they have vitrified?	couldn't I have been vitrifying? couldn't you have been vitrifying? couldn't he have been vitrifying? couldn't we have been vitrifying? couldn't you have been vitrifying? couldn't they have been vitrifying?