can sub
Regular verb: sub - subbed- subbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can sub
you can sub
he can sub
we can sub
you can sub
they can sub 	I can be subbing
you can be subbing
he can be subbing
we can be subbing
you can be subbing
they can be subbing	I can have subbed
you can have subbed
he can have subbed
we can have subbed
you can have subbed
they can have subbed	I can have been subbing
you can have been subbing
he can have been subbing
we can have been subbing
you can have been subbing
they can have been subbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't sub
you can't sub
he can't sub
we can't sub
you can't sub
they can't sub 	I can't be subbing
you can't be subbing
he can't be subbing
we can't be subbing
you can't be subbing
they can't be subbing	I can't have subbed
you can't have subbed
he can't have subbed
we can't have subbed
you can't have subbed
they can't have subbed	I can't have been subbing
you can't have been subbing
he can't have been subbing
we can't have been subbing
you can't have been subbing
they can't have been subbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I sub?
can you sub?
can he sub?
can we sub?
can you sub?
can they sub? 	can I be subbing?
can you be subbing?
can he be subbing?
can we be subbing?
can you be subbing?
can they be subbing? 	can I have subbed?
can you have subbed?
can he have subbed?
can we have subbed?
can you have subbed?
can they have subbed? 	can I have been subbing?
can you have been subbing?
can he have been subbing?
can we have been subbing?
can you have been subbing?
can they have been subbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I sub?
can't you sub?
can't he sub?
can't we sub?
can't you sub?
can't they sub? 	can't I be subbing?
can't you be subbing?
can't he be subbing?
can't we be subbing?
can't you be subbing?
can't they be subbing? 	can't I have subbed?
can't you have subbed?
can't he have subbed?
can't we have subbed?
can't you have subbed?
can't they have subbed? 	can't I have been subbing?
can't you have been subbing?
can't he have been subbing?
can't we have been subbing?
can't you have been subbing?
can't they have been subbing?