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 couldn't tusk you couldn't tusk he couldn't tusk we couldn't tusk you couldn't tusk they couldn't tusk	I couldn't be tusking you couldn't be tusking he couldn't be tusking we couldn't be tusking you couldn't be tusking they couldn't be tusking
Perfect	V-ing perfect
I couldn't have tusked you couldn't have tusked he couldn't have tusked we couldn't have tusked you couldn't have tusked they couldn't have tusked	I couldn't have been tusking you couldn't have been tusking he couldn't have been tusking we couldn't have been tusking you couldn't have been tusking they couldn't 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
couldn't I tusk? couldn't you tusk? couldn't he tusk? couldn't we tusk? couldn't you tusk? couldn't they tusk?	couldn't I be tusking? couldn't you be tusking? couldn't he be tusking? couldn't we be tusking? couldn't you be tusking? couldn't they be tusking?
Perfect	V-ing perfect
couldn't I have tusked? couldn't you have tusked? couldn't he have tusked? couldn't we have tusked? couldn't you have tusked? couldn't they have tusked?	couldn't I have been tusking? couldn't you have been tusking? couldn't he have been tusking? couldn't we have been tusking? couldn't you have been tusking? couldn't they have been tusking?