can mumble
Regular verb: mumble - mumbled- mumbled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can mumble
you can mumble
she can mumble
we can mumble
you can mumble
they can mumble 	I can be mumbling
you can be mumbling
she can be mumbling
we can be mumbling
you can be mumbling
they can be mumbling	I can have mumbled
you can have mumbled
she can have mumbled
we can have mumbled
you can have mumbled
they can have mumbled	I can have been mumbling
you can have been mumbling
she can have been mumbling
we can have been mumbling
you can have been mumbling
they can have been mumbling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot mumble
you cannot mumble
she cannot mumble
we cannot mumble
you cannot mumble
they cannot mumble 	I cannot be mumbling
you cannot be mumbling
she cannot be mumbling
we cannot be mumbling
you cannot be mumbling
they cannot be mumbling	I cannot have mumbled
you cannot have mumbled
she cannot have mumbled
we cannot have mumbled
you cannot have mumbled
they cannot have mumbled	I cannot have been mumbling
you cannot have been mumbling
she cannot have been mumbling
we cannot have been mumbling
you cannot have been mumbling
they cannot have been mumbling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I mumble?
can you mumble?
can she mumble?
can we mumble?
can you mumble?
can they mumble? 	can I be mumbling?
can you be mumbling?
can she be mumbling?
can we be mumbling?
can you be mumbling?
can they be mumbling? 	can I have mumbled?
can you have mumbled?
can she have mumbled?
can we have mumbled?
can you have mumbled?
can they have mumbled? 	can I have been mumbling?
can you have been mumbling?
can she have been mumbling?
can we have been mumbling?
can you have been mumbling?
can they have been mumbling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not mumble?
can you not mumble?
can she not mumble?
can we not mumble?
can you not mumble?
can they not mumble? 	can I not be mumbling?
can you not be mumbling?
can she not be mumbling?
can we not be mumbling?
can you not be mumbling?
can they not be mumbling? 	can I not have mumbled?
can you not have mumbled?
can she not have mumbled?
can we not have mumbled?
can you not have mumbled?
can they not have mumbled? 	can I not have been mumbling?
can you not have been mumbling?
can she not have been mumbling?
can we not have been mumbling?
can you not have been mumbling?
can they not have been mumbling?