can rub
Regular verb: rub - rubbed- rubbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can rub
you can rub
he can rub
we can rub
you can rub
they can rub 	I can be rubbing
you can be rubbing
he can be rubbing
we can be rubbing
you can be rubbing
they can be rubbing	I can have rubbed
you can have rubbed
he can have rubbed
we can have rubbed
you can have rubbed
they can have rubbed	I can have been rubbing
you can have been rubbing
he can have been rubbing
we can have been rubbing
you can have been rubbing
they can have been rubbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot rub
you cannot rub
he cannot rub
we cannot rub
you cannot rub
they cannot rub 	I cannot be rubbing
you cannot be rubbing
he cannot be rubbing
we cannot be rubbing
you cannot be rubbing
they cannot be rubbing	I cannot have rubbed
you cannot have rubbed
he cannot have rubbed
we cannot have rubbed
you cannot have rubbed
they cannot have rubbed	I cannot have been rubbing
you cannot have been rubbing
he cannot have been rubbing
we cannot have been rubbing
you cannot have been rubbing
they cannot have been rubbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I rub?
can you rub?
can he rub?
can we rub?
can you rub?
can they rub? 	can I be rubbing?
can you be rubbing?
can he be rubbing?
can we be rubbing?
can you be rubbing?
can they be rubbing? 	can I have rubbed?
can you have rubbed?
can he have rubbed?
can we have rubbed?
can you have rubbed?
can they have rubbed? 	can I have been rubbing?
can you have been rubbing?
can he have been rubbing?
can we have been rubbing?
can you have been rubbing?
can they have been rubbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not rub?
can you not rub?
can he not rub?
can we not rub?
can you not rub?
can they not rub? 	can I not be rubbing?
can you not be rubbing?
can he not be rubbing?
can we not be rubbing?
can you not be rubbing?
can they not be rubbing? 	can I not have rubbed?
can you not have rubbed?
can he not have rubbed?
can we not have rubbed?
can you not have rubbed?
can they not have rubbed? 	can I not have been rubbing?
can you not have been rubbing?
can he not have been rubbing?
can we not have been rubbing?
can you not have been rubbing?
can they not have been rubbing?