can whiten
Regular verb: whiten - whitened- whitened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can whiten
you can whiten
he can whiten
we can whiten
you can whiten
they can whiten 	I can be whitening
you can be whitening
he can be whitening
we can be whitening
you can be whitening
they can be whitening	I can have whitened
you can have whitened
he can have whitened
we can have whitened
you can have whitened
they can have whitened	I can have been whitening
you can have been whitening
he can have been whitening
we can have been whitening
you can have been whitening
they can have been whitening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot whiten
you cannot whiten
he cannot whiten
we cannot whiten
you cannot whiten
they cannot whiten 	I cannot be whitening
you cannot be whitening
he cannot be whitening
we cannot be whitening
you cannot be whitening
they cannot be whitening	I cannot have whitened
you cannot have whitened
he cannot have whitened
we cannot have whitened
you cannot have whitened
they cannot have whitened	I cannot have been whitening
you cannot have been whitening
he cannot have been whitening
we cannot have been whitening
you cannot have been whitening
they cannot have been whitening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I whiten?
can you whiten?
can he whiten?
can we whiten?
can you whiten?
can they whiten? 	can I be whitening?
can you be whitening?
can he be whitening?
can we be whitening?
can you be whitening?
can they be whitening? 	can I have whitened?
can you have whitened?
can he have whitened?
can we have whitened?
can you have whitened?
can they have whitened? 	can I have been whitening?
can you have been whitening?
can he have been whitening?
can we have been whitening?
can you have been whitening?
can they have been whitening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not whiten?
can you not whiten?
can he not whiten?
can we not whiten?
can you not whiten?
can they not whiten? 	can I not be whitening?
can you not be whitening?
can he not be whitening?
can we not be whitening?
can you not be whitening?
can they not be whitening? 	can I not have whitened?
can you not have whitened?
can he not have whitened?
can we not have whitened?
can you not have whitened?
can they not have whitened? 	can I not have been whitening?
can you not have been whitening?
can he not have been whitening?
can we not have been whitening?
can you not have been whitening?
can they not have been whitening?