I can mumble you can mumble she can mumble we can mumble you can mumble they can mumble
V-ing form
I can be mumbling you can be mumbling she can be mumbling we can be mumbling you can be mumbling they can be mumbling
Perfect
I can have mumbled you can have mumbled she can have mumbled we can have mumbled you can have mumbled they can have mumbled
V-ing perfect
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
I cannot mumble you cannot mumble she cannot mumble we cannot mumble you cannot mumble they cannot mumble
V-ing form
I cannot be mumbling you cannot be mumbling she cannot be mumbling we cannot be mumbling you cannot be mumbling they cannot be mumbling
Perfect
I cannot have mumbled you cannot have mumbled she cannot have mumbled we cannot have mumbled you cannot have mumbled they cannot have mumbled
V-ing perfect
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
can I mumble? can you mumble? can she mumble? can we mumble? can you mumble? can they mumble?
V-ing form
can I be mumbling? can you be mumbling? can she be mumbling? can we be mumbling? can you be mumbling? can they be mumbling?
Perfect
can I have mumbled? can you have mumbled? can she have mumbled? can we have mumbled? can you have mumbled? can they have mumbled?
V-ing perfect
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
can I not mumble? can you not mumble? can she not mumble? can we not mumble? can you not mumble? can they not mumble?
V-ing form
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?
Perfect
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?
V-ing perfect
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?