English verb conjugation
COULD PIERCE

Regular verb: pierce - pierced - pierced

Affirmation

Simple form	V-ing form
I could pierce you could pierce he could pierce we could pierce you could pierce they could pierce	I could be piercing you could be piercing he could be piercing we could be piercing you could be piercing they could be piercing
Perfect	V-ing perfect
I could have pierced you could have pierced he could have pierced we could have pierced you could have pierced they could have pierced	I could have been piercing you could have been piercing he could have been piercing we could have been piercing you could have been piercing they could have been piercing

Negation

Simple form	V-ing form
I couldn't pierce you couldn't pierce he couldn't pierce we couldn't pierce you couldn't pierce they couldn't pierce	I couldn't be piercing you couldn't be piercing he couldn't be piercing we couldn't be piercing you couldn't be piercing they couldn't be piercing
Perfect	V-ing perfect
I couldn't have pierced you couldn't have pierced he couldn't have pierced we couldn't have pierced you couldn't have pierced they couldn't have pierced	I couldn't have been piercing you couldn't have been piercing he couldn't have been piercing we couldn't have been piercing you couldn't have been piercing they couldn't have been piercing

Interrogative form

Simple form	V-ing form
could I pierce? could you pierce? could he pierce? could we pierce? could you pierce? could they pierce?	could I be piercing? could you be piercing? could he be piercing? could we be piercing? could you be piercing? could they be piercing?
Perfect	V-ing perfect
could I have pierced? could you have pierced? could he have pierced? could we have pierced? could you have pierced? could they have pierced?	could I have been piercing? could you have been piercing? could he have been piercing? could we have been piercing? could you have been piercing? could they have been piercing?

Interro-negative form

Simple form	V-ing form
couldn't I pierce? couldn't you pierce? couldn't he pierce? couldn't we pierce? couldn't you pierce? couldn't they pierce?	couldn't I be piercing? couldn't you be piercing? couldn't he be piercing? couldn't we be piercing? couldn't you be piercing? couldn't they be piercing?
Perfect	V-ing perfect
couldn't I have pierced? couldn't you have pierced? couldn't he have pierced? couldn't we have pierced? couldn't you have pierced? couldn't they have pierced?	couldn't I have been piercing? couldn't you have been piercing? couldn't he have been piercing? couldn't we have been piercing? couldn't you have been piercing? couldn't they have been piercing?