could rank
Regular verb: rank - ranked- ranked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could rank
you could rank
he could rank
we could rank
you could rank
they could rank 	I could be ranking
you could be ranking
he could be ranking
we could be ranking
you could be ranking
they could be ranking	I could have ranked
you could have ranked
he could have ranked
we could have ranked
you could have ranked
they could have ranked	I could have been ranking
you could have been ranking
he could have been ranking
we could have been ranking
you could have been ranking
they could have been ranking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't rank
you couldn't rank
he couldn't rank
we couldn't rank
you couldn't rank
they couldn't rank 	I couldn't be ranking
you couldn't be ranking
he couldn't be ranking
we couldn't be ranking
you couldn't be ranking
they couldn't be ranking	I couldn't have ranked
you couldn't have ranked
he couldn't have ranked
we couldn't have ranked
you couldn't have ranked
they couldn't have ranked	I couldn't have been ranking
you couldn't have been ranking
he couldn't have been ranking
we couldn't have been ranking
you couldn't have been ranking
they couldn't have been ranking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I rank?
could you rank?
could he rank?
could we rank?
could you rank?
could they rank? 	could I be ranking?
could you be ranking?
could he be ranking?
could we be ranking?
could you be ranking?
could they be ranking? 	could I have ranked?
could you have ranked?
could he have ranked?
could we have ranked?
could you have ranked?
could they have ranked? 	could I have been ranking?
could you have been ranking?
could he have been ranking?
could we have been ranking?
could you have been ranking?
could they have been ranking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I rank?
couldn't you rank?
couldn't he rank?
couldn't we rank?
couldn't you rank?
couldn't they rank? 	couldn't I be ranking?
couldn't you be ranking?
couldn't he be ranking?
couldn't we be ranking?
couldn't you be ranking?
couldn't they be ranking? 	couldn't I have ranked?
couldn't you have ranked?
couldn't he have ranked?
couldn't we have ranked?
couldn't you have ranked?
couldn't they have ranked? 	couldn't I have been ranking?
couldn't you have been ranking?
couldn't he have been ranking?
couldn't we have been ranking?
couldn't you have been ranking?
couldn't they have been ranking?