English verb conjugation
COULD TENON

Regular verb: tenon - tenoned - tenoned

Affirmation

Simple form	V-ing form
I could tenon you could tenon he could tenon we could tenon you could tenon they could tenon	I could be tenoning you could be tenoning he could be tenoning we could be tenoning you could be tenoning they could be tenoning
Perfect	V-ing perfect
I could have tenoned you could have tenoned he could have tenoned we could have tenoned you could have tenoned they could have tenoned	I could have been tenoning you could have been tenoning he could have been tenoning we could have been tenoning you could have been tenoning they could have been tenoning

Negation

Simple form	V-ing form
I couldn't tenon you couldn't tenon he couldn't tenon we couldn't tenon you couldn't tenon they couldn't tenon	I couldn't be tenoning you couldn't be tenoning he couldn't be tenoning we couldn't be tenoning you couldn't be tenoning they couldn't be tenoning
Perfect	V-ing perfect
I couldn't have tenoned you couldn't have tenoned he couldn't have tenoned we couldn't have tenoned you couldn't have tenoned they couldn't have tenoned	I couldn't have been tenoning you couldn't have been tenoning he couldn't have been tenoning we couldn't have been tenoning you couldn't have been tenoning they couldn't have been tenoning

Interrogative form

Simple form	V-ing form
could I tenon? could you tenon? could he tenon? could we tenon? could you tenon? could they tenon?	could I be tenoning? could you be tenoning? could he be tenoning? could we be tenoning? could you be tenoning? could they be tenoning?
Perfect	V-ing perfect
could I have tenoned? could you have tenoned? could he have tenoned? could we have tenoned? could you have tenoned? could they have tenoned?	could I have been tenoning? could you have been tenoning? could he have been tenoning? could we have been tenoning? could you have been tenoning? could they have been tenoning?

Interro-negative form

Simple form	V-ing form
couldn't I tenon? couldn't you tenon? couldn't he tenon? couldn't we tenon? couldn't you tenon? couldn't they tenon?	couldn't I be tenoning? couldn't you be tenoning? couldn't he be tenoning? couldn't we be tenoning? couldn't you be tenoning? couldn't they be tenoning?
Perfect	V-ing perfect
couldn't I have tenoned? couldn't you have tenoned? couldn't he have tenoned? couldn't we have tenoned? couldn't you have tenoned? couldn't they have tenoned?	couldn't I have been tenoning? couldn't you have been tenoning? couldn't he have been tenoning? couldn't we have been tenoning? couldn't you have been tenoning? couldn't they have been tenoning?