could rumble
Regular verb: rumble - rumbled- rumbled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could rumble
you could rumble
he could rumble
we could rumble
you could rumble
they could rumble 	I could be rumbling
you could be rumbling
he could be rumbling
we could be rumbling
you could be rumbling
they could be rumbling	I could have rumbled
you could have rumbled
he could have rumbled
we could have rumbled
you could have rumbled
they could have rumbled	I could have been rumbling
you could have been rumbling
he could have been rumbling
we could have been rumbling
you could have been rumbling
they could have been rumbling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't rumble
you couldn't rumble
he couldn't rumble
we couldn't rumble
you couldn't rumble
they couldn't rumble 	I couldn't be rumbling
you couldn't be rumbling
he couldn't be rumbling
we couldn't be rumbling
you couldn't be rumbling
they couldn't be rumbling	I couldn't have rumbled
you couldn't have rumbled
he couldn't have rumbled
we couldn't have rumbled
you couldn't have rumbled
they couldn't have rumbled	I couldn't have been rumbling
you couldn't have been rumbling
he couldn't have been rumbling
we couldn't have been rumbling
you couldn't have been rumbling
they couldn't have been rumbling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I rumble?
could you rumble?
could he rumble?
could we rumble?
could you rumble?
could they rumble? 	could I be rumbling?
could you be rumbling?
could he be rumbling?
could we be rumbling?
could you be rumbling?
could they be rumbling? 	could I have rumbled?
could you have rumbled?
could he have rumbled?
could we have rumbled?
could you have rumbled?
could they have rumbled? 	could I have been rumbling?
could you have been rumbling?
could he have been rumbling?
could we have been rumbling?
could you have been rumbling?
could they have been rumbling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I rumble?
couldn't you rumble?
couldn't he rumble?
couldn't we rumble?
couldn't you rumble?
couldn't they rumble? 	couldn't I be rumbling?
couldn't you be rumbling?
couldn't he be rumbling?
couldn't we be rumbling?
couldn't you be rumbling?
couldn't they be rumbling? 	couldn't I have rumbled?
couldn't you have rumbled?
couldn't he have rumbled?
couldn't we have rumbled?
couldn't you have rumbled?
couldn't they have rumbled? 	couldn't I have been rumbling?
couldn't you have been rumbling?
couldn't he have been rumbling?
couldn't we have been rumbling?
couldn't you have been rumbling?
couldn't they have been rumbling?