English verb conjugation
COULD NITRIFY

Regular verb: nitrify - nitrified - nitrified

Affirmation

Simple form	V-ing form
I could nitrify you could nitrify she could nitrify we could nitrify you could nitrify they could nitrify	I could be nitrifying you could be nitrifying she could be nitrifying we could be nitrifying you could be nitrifying they could be nitrifying
Perfect	V-ing perfect
I could have nitrified you could have nitrified she could have nitrified we could have nitrified you could have nitrified they could have nitrified	I could have been nitrifying you could have been nitrifying she could have been nitrifying we could have been nitrifying you could have been nitrifying they could have been nitrifying

Negation

Simple form	V-ing form
I couldn't nitrify you couldn't nitrify she couldn't nitrify we couldn't nitrify you couldn't nitrify they couldn't nitrify	I couldn't be nitrifying you couldn't be nitrifying she couldn't be nitrifying we couldn't be nitrifying you couldn't be nitrifying they couldn't be nitrifying
Perfect	V-ing perfect
I couldn't have nitrified you couldn't have nitrified she couldn't have nitrified we couldn't have nitrified you couldn't have nitrified they couldn't have nitrified	I couldn't have been nitrifying you couldn't have been nitrifying she couldn't have been nitrifying we couldn't have been nitrifying you couldn't have been nitrifying they couldn't have been nitrifying

Interrogative form

Simple form	V-ing form
could I nitrify? could you nitrify? could she nitrify? could we nitrify? could you nitrify? could they nitrify?	could I be nitrifying? could you be nitrifying? could she be nitrifying? could we be nitrifying? could you be nitrifying? could they be nitrifying?
Perfect	V-ing perfect
could I have nitrified? could you have nitrified? could she have nitrified? could we have nitrified? could you have nitrified? could they have nitrified?	could I have been nitrifying? could you have been nitrifying? could she have been nitrifying? could we have been nitrifying? could you have been nitrifying? could they have been nitrifying?

Interro-negative form

Simple form	V-ing form
couldn't I nitrify? couldn't you nitrify? couldn't she nitrify? couldn't we nitrify? couldn't you nitrify? couldn't they nitrify?	couldn't I be nitrifying? couldn't you be nitrifying? couldn't she be nitrifying? couldn't we be nitrifying? couldn't you be nitrifying? couldn't they be nitrifying?
Perfect	V-ing perfect
couldn't I have nitrified? couldn't you have nitrified? couldn't she have nitrified? couldn't we have nitrified? couldn't you have nitrified? couldn't they have nitrified?	couldn't I have been nitrifying? couldn't you have been nitrifying? couldn't she have been nitrifying? couldn't we have been nitrifying? couldn't you have been nitrifying? couldn't they have been nitrifying?