could denature
Regular verb: denature - denatured- denatured

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could denature
you could denature
he could denature
we could denature
you could denature
they could denature 	I could be denaturing
you could be denaturing
he could be denaturing
we could be denaturing
you could be denaturing
they could be denaturing	I could have denatured
you could have denatured
he could have denatured
we could have denatured
you could have denatured
they could have denatured	I could have been denaturing
you could have been denaturing
he could have been denaturing
we could have been denaturing
you could have been denaturing
they could have been denaturing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't denature
you couldn't denature
he couldn't denature
we couldn't denature
you couldn't denature
they couldn't denature 	I couldn't be denaturing
you couldn't be denaturing
he couldn't be denaturing
we couldn't be denaturing
you couldn't be denaturing
they couldn't be denaturing	I couldn't have denatured
you couldn't have denatured
he couldn't have denatured
we couldn't have denatured
you couldn't have denatured
they couldn't have denatured	I couldn't have been denaturing
you couldn't have been denaturing
he couldn't have been denaturing
we couldn't have been denaturing
you couldn't have been denaturing
they couldn't have been denaturing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I denature?
could you denature?
could he denature?
could we denature?
could you denature?
could they denature? 	could I be denaturing?
could you be denaturing?
could he be denaturing?
could we be denaturing?
could you be denaturing?
could they be denaturing? 	could I have denatured?
could you have denatured?
could he have denatured?
could we have denatured?
could you have denatured?
could they have denatured? 	could I have been denaturing?
could you have been denaturing?
could he have been denaturing?
could we have been denaturing?
could you have been denaturing?
could they have been denaturing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I denature?
couldn't you denature?
couldn't he denature?
couldn't we denature?
couldn't you denature?
couldn't they denature? 	couldn't I be denaturing?
couldn't you be denaturing?
couldn't he be denaturing?
couldn't we be denaturing?
couldn't you be denaturing?
couldn't they be denaturing? 	couldn't I have denatured?
couldn't you have denatured?
couldn't he have denatured?
couldn't we have denatured?
couldn't you have denatured?
couldn't they have denatured? 	couldn't I have been denaturing?
couldn't you have been denaturing?
couldn't he have been denaturing?
couldn't we have been denaturing?
couldn't you have been denaturing?
couldn't they have been denaturing?