English verb conjugation
CAN CONTEST

Regular verb: contest - contested - contested

Affirmation

Simple form	V-ing form
I can contest you can contest he can contest we can contest you can contest they can contest	I can be contesting you can be contesting he can be contesting we can be contesting you can be contesting they can be contesting
Perfect	V-ing perfect
I can have contested you can have contested he can have contested we can have contested you can have contested they can have contested	I can have been contesting you can have been contesting he can have been contesting we can have been contesting you can have been contesting they can have been contesting

Negation

Simple form	V-ing form
I can't contest you can't contest he can't contest we can't contest you can't contest they can't contest	I can't be contesting you can't be contesting he can't be contesting we can't be contesting you can't be contesting they can't be contesting
Perfect	V-ing perfect
I can't have contested you can't have contested he can't have contested we can't have contested you can't have contested they can't have contested	I can't have been contesting you can't have been contesting he can't have been contesting we can't have been contesting you can't have been contesting they can't have been contesting

Interrogative form

Simple form	V-ing form
can I contest? can you contest? can he contest? can we contest? can you contest? can they contest?	can I be contesting? can you be contesting? can he be contesting? can we be contesting? can you be contesting? can they be contesting?
Perfect	V-ing perfect
can I have contested? can you have contested? can he have contested? can we have contested? can you have contested? can they have contested?	can I have been contesting? can you have been contesting? can he have been contesting? can we have been contesting? can you have been contesting? can they have been contesting?

Interro-negative form

Simple form	V-ing form
can't I contest? can't you contest? can't he contest? can't we contest? can't you contest? can't they contest?	can't I be contesting? can't you be contesting? can't he be contesting? can't we be contesting? can't you be contesting? can't they be contesting?
Perfect	V-ing perfect
can't I have contested? can't you have contested? can't he have contested? can't we have contested? can't you have contested? can't they have contested?	can't I have been contesting? can't you have been contesting? can't he have been contesting? can't we have been contesting? can't you have been contesting? can't they have been contesting?