English verb conjugation
CAN HOWL

Regular verb: howl - howled - howled

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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
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
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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?