English verb conjugation
COULD TUSK

Regular verb: tusk - tusked - tusked

Affirmation

Simple form	V-ing form
I could tusk you could tusk he could tusk we could tusk you could tusk they could tusk	I could be tusking you could be tusking he could be tusking we could be tusking you could be tusking they could be tusking
Perfect	V-ing perfect
I could have tusked you could have tusked he could have tusked we could have tusked you could have tusked they could have tusked	I could have been tusking you could have been tusking he could have been tusking we could have been tusking you could have been tusking they could have been tusking

Negation

Simple form	V-ing form
I could not tusk you could not tusk he could not tusk we could not tusk you could not tusk they could not tusk	I could not be tusking you could not be tusking he could not be tusking we could not be tusking you could not be tusking they could not be tusking
Perfect	V-ing perfect
I could not have tusked you could not have tusked he could not have tusked we could not have tusked you could not have tusked they could not have tusked	I could not have been tusking you could not have been tusking he could not have been tusking we could not have been tusking you could not have been tusking they could not have been tusking

Interrogative form

Simple form	V-ing form
could I tusk? could you tusk? could he tusk? could we tusk? could you tusk? could they tusk?	could I be tusking? could you be tusking? could he be tusking? could we be tusking? could you be tusking? could they be tusking?
Perfect	V-ing perfect
could I have tusked? could you have tusked? could he have tusked? could we have tusked? could you have tusked? could they have tusked?	could I have been tusking? could you have been tusking? could he have been tusking? could we have been tusking? could you have been tusking? could they have been tusking?

Interro-negative form

Simple form	V-ing form
could I not tusk? could you not tusk? could he not tusk? could we not tusk? could you not tusk? could they not tusk?	could I not be tusking? could you not be tusking? could he not be tusking? could we not be tusking? could you not be tusking? could they not be tusking?
Perfect	V-ing perfect
could I not have tusked? could you not have tusked? could he not have tusked? could we not have tusked? could you not have tusked? could they not have tusked?	could I not have been tusking? could you not have been tusking? could he not have been tusking? could we not have been tusking? could you not have been tusking? could they not have been tusking?