English verb conjugation
CAN TUMBLE

Regular verb: tumble - tumbled - tumbled

Affirmation

Simple form	V-ing form
I can tumble you can tumble she can tumble we can tumble you can tumble they can tumble	I can be tumbling you can be tumbling she can be tumbling we can be tumbling you can be tumbling they can be tumbling
Perfect	V-ing perfect
I can have tumbled you can have tumbled she can have tumbled we can have tumbled you can have tumbled they can have tumbled	I can have been tumbling you can have been tumbling she can have been tumbling we can have been tumbling you can have been tumbling they can have been tumbling

Negation

Simple form	V-ing form
I cannot tumble you cannot tumble she cannot tumble we cannot tumble you cannot tumble they cannot tumble	I cannot be tumbling you cannot be tumbling she cannot be tumbling we cannot be tumbling you cannot be tumbling they cannot be tumbling
Perfect	V-ing perfect
I cannot have tumbled you cannot have tumbled she cannot have tumbled we cannot have tumbled you cannot have tumbled they cannot have tumbled	I cannot have been tumbling you cannot have been tumbling she cannot have been tumbling we cannot have been tumbling you cannot have been tumbling they cannot have been tumbling

Interrogative form

Simple form	V-ing form
can I tumble? can you tumble? can she tumble? can we tumble? can you tumble? can they tumble?	can I be tumbling? can you be tumbling? can she be tumbling? can we be tumbling? can you be tumbling? can they be tumbling?
Perfect	V-ing perfect
can I have tumbled? can you have tumbled? can she have tumbled? can we have tumbled? can you have tumbled? can they have tumbled?	can I have been tumbling? can you have been tumbling? can she have been tumbling? can we have been tumbling? can you have been tumbling? can they have been tumbling?

Interro-negative form

Simple form	V-ing form
can I not tumble? can you not tumble? can she not tumble? can we not tumble? can you not tumble? can they not tumble?	can I not be tumbling? can you not be tumbling? can she not be tumbling? can we not be tumbling? can you not be tumbling? can they not be tumbling?
Perfect	V-ing perfect
can I not have tumbled? can you not have tumbled? can she not have tumbled? can we not have tumbled? can you not have tumbled? can they not have tumbled?	can I not have been tumbling? can you not have been tumbling? can she not have been tumbling? can we not have been tumbling? can you not have been tumbling? can they not have been tumbling?