can howl
Regular verb: howl - howled- howled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can howl
you can howl
he can howl
we can howl
you can howl
they can howl 	I can be howling
you can be howling
he can be howling
we can be howling
you can be howling
they can be howling	I can have howled
you can have howled
he can have howled
we can have howled
you can have howled
they can have howled	I can have been howling
you can have been howling
he can have been howling
we can have been howling
you can have been howling
they can have been howling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't howl
you can't howl
he can't howl
we can't howl
you can't howl
they can't howl 	I can't be howling
you can't be howling
he can't be howling
we can't be howling
you can't be howling
they can't be howling	I can't have howled
you can't have howled
he can't have howled
we can't have howled
you can't have howled
they can't have howled	I can't have been howling
you can't have been howling
he can't have been howling
we can't have been howling
you can't have been howling
they can't have been howling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I howl?
can you howl?
can he howl?
can we howl?
can you howl?
can they howl? 	can I be howling?
can you be howling?
can he be howling?
can we be howling?
can you be howling?
can they be howling? 	can I have howled?
can you have howled?
can he have howled?
can we have howled?
can you have howled?
can they have howled? 	can I have been howling?
can you have been howling?
can he have been howling?
can we have been howling?
can you have been howling?
can they have been howling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I howl?
can't you howl?
can't he howl?
can't we howl?
can't you howl?
can't they howl? 	can't I be howling?
can't you be howling?
can't he be howling?
can't we be howling?
can't you be howling?
can't they be howling? 	can't I have howled?
can't you have howled?
can't he have howled?
can't we have howled?
can't you have howled?
can't they have howled? 	can't I have been howling?
can't you have been howling?
can't he have been howling?
can't we have been howling?
can't you have been howling?
can't they have been howling?