can pen
Regular verb: pen - penned- penned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can pen
you can pen
she can pen
we can pen
you can pen
they can pen 	I can be penning
you can be penning
she can be penning
we can be penning
you can be penning
they can be penning	I can have penned
you can have penned
she can have penned
we can have penned
you can have penned
they can have penned	I can have been penning
you can have been penning
she can have been penning
we can have been penning
you can have been penning
they can have been penning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot pen
you cannot pen
she cannot pen
we cannot pen
you cannot pen
they cannot pen 	I cannot be penning
you cannot be penning
she cannot be penning
we cannot be penning
you cannot be penning
they cannot be penning	I cannot have penned
you cannot have penned
she cannot have penned
we cannot have penned
you cannot have penned
they cannot have penned	I cannot have been penning
you cannot have been penning
she cannot have been penning
we cannot have been penning
you cannot have been penning
they cannot have been penning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I pen?
can you pen?
can she pen?
can we pen?
can you pen?
can they pen? 	can I be penning?
can you be penning?
can she be penning?
can we be penning?
can you be penning?
can they be penning? 	can I have penned?
can you have penned?
can she have penned?
can we have penned?
can you have penned?
can they have penned? 	can I have been penning?
can you have been penning?
can she have been penning?
can we have been penning?
can you have been penning?
can they have been penning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not pen?
can you not pen?
can she not pen?
can we not pen?
can you not pen?
can they not pen? 	can I not be penning?
can you not be penning?
can she not be penning?
can we not be penning?
can you not be penning?
can they not be penning? 	can I not have penned?
can you not have penned?
can she not have penned?
can we not have penned?
can you not have penned?
can they not have penned? 	can I not have been penning?
can you not have been penning?
can she not have been penning?
can we not have been penning?
can you not have been penning?
can they not have been penning?