English verb conjugation
COULD PREBOARD

Regular verb: preboard - preboarded - preboarded

Affirmation

Simple form	V-ing form
I could preboard you could preboard he could preboard we could preboard you could preboard they could preboard	I could be preboarding you could be preboarding he could be preboarding we could be preboarding you could be preboarding they could be preboarding
Perfect	V-ing perfect
I could have preboarded you could have preboarded he could have preboarded we could have preboarded you could have preboarded they could have preboarded	I could have been preboarding you could have been preboarding he could have been preboarding we could have been preboarding you could have been preboarding they could have been preboarding

Negation

Simple form	V-ing form
I couldn't preboard you couldn't preboard he couldn't preboard we couldn't preboard you couldn't preboard they couldn't preboard	I couldn't be preboarding you couldn't be preboarding he couldn't be preboarding we couldn't be preboarding you couldn't be preboarding they couldn't be preboarding
Perfect	V-ing perfect
I couldn't have preboarded you couldn't have preboarded he couldn't have preboarded we couldn't have preboarded you couldn't have preboarded they couldn't have preboarded	I couldn't have been preboarding you couldn't have been preboarding he couldn't have been preboarding we couldn't have been preboarding you couldn't have been preboarding they couldn't have been preboarding

Interrogative form

Simple form	V-ing form
could I preboard? could you preboard? could he preboard? could we preboard? could you preboard? could they preboard?	could I be preboarding? could you be preboarding? could he be preboarding? could we be preboarding? could you be preboarding? could they be preboarding?
Perfect	V-ing perfect
could I have preboarded? could you have preboarded? could he have preboarded? could we have preboarded? could you have preboarded? could they have preboarded?	could I have been preboarding? could you have been preboarding? could he have been preboarding? could we have been preboarding? could you have been preboarding? could they have been preboarding?

Interro-negative form

Simple form	V-ing form
couldn't I preboard? couldn't you preboard? couldn't he preboard? couldn't we preboard? couldn't you preboard? couldn't they preboard?	couldn't I be preboarding? couldn't you be preboarding? couldn't he be preboarding? couldn't we be preboarding? couldn't you be preboarding? couldn't they be preboarding?
Perfect	V-ing perfect
couldn't I have preboarded? couldn't you have preboarded? couldn't he have preboarded? couldn't we have preboarded? couldn't you have preboarded? couldn't they have preboarded?	couldn't I have been preboarding? couldn't you have been preboarding? couldn't he have been preboarding? couldn't we have been preboarding? couldn't you have been preboarding? couldn't they have been preboarding?