could revise
Regular verb: revise - revised- revised

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could revise
you could revise
he could revise
we could revise
you could revise
they could revise 	I could be revising
you could be revising
he could be revising
we could be revising
you could be revising
they could be revising	I could have revised
you could have revised
he could have revised
we could have revised
you could have revised
they could have revised	I could have been revising
you could have been revising
he could have been revising
we could have been revising
you could have been revising
they could have been revising	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't revise
you couldn't revise
he couldn't revise
we couldn't revise
you couldn't revise
they couldn't revise 	I couldn't be revising
you couldn't be revising
he couldn't be revising
we couldn't be revising
you couldn't be revising
they couldn't be revising	I couldn't have revised
you couldn't have revised
he couldn't have revised
we couldn't have revised
you couldn't have revised
they couldn't have revised	I couldn't have been revising
you couldn't have been revising
he couldn't have been revising
we couldn't have been revising
you couldn't have been revising
they couldn't have been revising	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I revise?
could you revise?
could he revise?
could we revise?
could you revise?
could they revise? 	could I be revising?
could you be revising?
could he be revising?
could we be revising?
could you be revising?
could they be revising? 	could I have revised?
could you have revised?
could he have revised?
could we have revised?
could you have revised?
could they have revised? 	could I have been revising?
could you have been revising?
could he have been revising?
could we have been revising?
could you have been revising?
could they have been revising? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I revise?
couldn't you revise?
couldn't he revise?
couldn't we revise?
couldn't you revise?
couldn't they revise? 	couldn't I be revising?
couldn't you be revising?
couldn't he be revising?
couldn't we be revising?
couldn't you be revising?
couldn't they be revising? 	couldn't I have revised?
couldn't you have revised?
couldn't he have revised?
couldn't we have revised?
couldn't you have revised?
couldn't they have revised? 	couldn't I have been revising?
couldn't you have been revising?
couldn't he have been revising?
couldn't we have been revising?
couldn't you have been revising?
couldn't they have been revising?