English verb conjugation
COULD SKATEBOARD

Regular verb: skateboard - skateboarded - skateboarded

Affirmation

Simple form	V-ing form
I could skateboard you could skateboard he could skateboard we could skateboard you could skateboard they could skateboard	I could be skateboarding you could be skateboarding he could be skateboarding we could be skateboarding you could be skateboarding they could be skateboarding
Perfect	V-ing perfect
I could have skateboarded you could have skateboarded he could have skateboarded we could have skateboarded you could have skateboarded they could have skateboarded	I could have been skateboarding you could have been skateboarding he could have been skateboarding we could have been skateboarding you could have been skateboarding they could have been skateboarding

Negation

Simple form	V-ing form
I couldn't skateboard you couldn't skateboard he couldn't skateboard we couldn't skateboard you couldn't skateboard they couldn't skateboard	I couldn't be skateboarding you couldn't be skateboarding he couldn't be skateboarding we couldn't be skateboarding you couldn't be skateboarding they couldn't be skateboarding
Perfect	V-ing perfect
I couldn't have skateboarded you couldn't have skateboarded he couldn't have skateboarded we couldn't have skateboarded you couldn't have skateboarded they couldn't have skateboarded	I couldn't have been skateboarding you couldn't have been skateboarding he couldn't have been skateboarding we couldn't have been skateboarding you couldn't have been skateboarding they couldn't have been skateboarding

Interrogative form

Simple form	V-ing form
could I skateboard? could you skateboard? could he skateboard? could we skateboard? could you skateboard? could they skateboard?	could I be skateboarding? could you be skateboarding? could he be skateboarding? could we be skateboarding? could you be skateboarding? could they be skateboarding?
Perfect	V-ing perfect
could I have skateboarded? could you have skateboarded? could he have skateboarded? could we have skateboarded? could you have skateboarded? could they have skateboarded?	could I have been skateboarding? could you have been skateboarding? could he have been skateboarding? could we have been skateboarding? could you have been skateboarding? could they have been skateboarding?

Interro-negative form

Simple form	V-ing form
couldn't I skateboard? couldn't you skateboard? couldn't he skateboard? couldn't we skateboard? couldn't you skateboard? couldn't they skateboard?	couldn't I be skateboarding? couldn't you be skateboarding? couldn't he be skateboarding? couldn't we be skateboarding? couldn't you be skateboarding? couldn't they be skateboarding?
Perfect	V-ing perfect
couldn't I have skateboarded? couldn't you have skateboarded? couldn't he have skateboarded? couldn't we have skateboarded? couldn't you have skateboarded? couldn't they have skateboarded?	couldn't I have been skateboarding? couldn't you have been skateboarding? couldn't he have been skateboarding? couldn't we have been skateboarding? couldn't you have been skateboarding? couldn't they have been skateboarding?