English verb conjugation
CAN UNDERUSE

Regular verb: underuse - underused - underused

Affirmation

Simple form	V-ing form
I can underuse you can underuse he can underuse we can underuse you can underuse they can underuse	I can be underusing you can be underusing he can be underusing we can be underusing you can be underusing they can be underusing
Perfect	V-ing perfect
I can have underused you can have underused he can have underused we can have underused you can have underused they can have underused	I can have been underusing you can have been underusing he can have been underusing we can have been underusing you can have been underusing they can have been underusing

Negation

Simple form	V-ing form
I can't underuse you can't underuse he can't underuse we can't underuse you can't underuse they can't underuse	I can't be underusing you can't be underusing he can't be underusing we can't be underusing you can't be underusing they can't be underusing
Perfect	V-ing perfect
I can't have underused you can't have underused he can't have underused we can't have underused you can't have underused they can't have underused	I can't have been underusing you can't have been underusing he can't have been underusing we can't have been underusing you can't have been underusing they can't have been underusing

Interrogative form

Simple form	V-ing form
can I underuse? can you underuse? can he underuse? can we underuse? can you underuse? can they underuse?	can I be underusing? can you be underusing? can he be underusing? can we be underusing? can you be underusing? can they be underusing?
Perfect	V-ing perfect
can I have underused? can you have underused? can he have underused? can we have underused? can you have underused? can they have underused?	can I have been underusing? can you have been underusing? can he have been underusing? can we have been underusing? can you have been underusing? can they have been underusing?

Interro-negative form

Simple form	V-ing form
can't I underuse? can't you underuse? can't he underuse? can't we underuse? can't you underuse? can't they underuse?	can't I be underusing? can't you be underusing? can't he be underusing? can't we be underusing? can't you be underusing? can't they be underusing?
Perfect	V-ing perfect
can't I have underused? can't you have underused? can't he have underused? can't we have underused? can't you have underused? can't they have underused?	can't I have been underusing? can't you have been underusing? can't he have been underusing? can't we have been underusing? can't you have been underusing? can't they have been underusing?