English verb conjugation
COULD PUNCTURE

Regular verb: puncture - punctured - punctured

Affirmation

Simple form	V-ing form
I could puncture you could puncture she could puncture we could puncture you could puncture they could puncture	I could be puncturing you could be puncturing she could be puncturing we could be puncturing you could be puncturing they could be puncturing
Perfect	V-ing perfect
I could have punctured you could have punctured she could have punctured we could have punctured you could have punctured they could have punctured	I could have been puncturing you could have been puncturing she could have been puncturing we could have been puncturing you could have been puncturing they could have been puncturing

Negation

Simple form	V-ing form
I couldn't puncture you couldn't puncture she couldn't puncture we couldn't puncture you couldn't puncture they couldn't puncture	I couldn't be puncturing you couldn't be puncturing she couldn't be puncturing we couldn't be puncturing you couldn't be puncturing they couldn't be puncturing
Perfect	V-ing perfect
I couldn't have punctured you couldn't have punctured she couldn't have punctured we couldn't have punctured you couldn't have punctured they couldn't have punctured	I couldn't have been puncturing you couldn't have been puncturing she couldn't have been puncturing we couldn't have been puncturing you couldn't have been puncturing they couldn't have been puncturing

Interrogative form

Simple form	V-ing form
could I puncture? could you puncture? could she puncture? could we puncture? could you puncture? could they puncture?	could I be puncturing? could you be puncturing? could she be puncturing? could we be puncturing? could you be puncturing? could they be puncturing?
Perfect	V-ing perfect
could I have punctured? could you have punctured? could she have punctured? could we have punctured? could you have punctured? could they have punctured?	could I have been puncturing? could you have been puncturing? could she have been puncturing? could we have been puncturing? could you have been puncturing? could they have been puncturing?

Interro-negative form

Simple form	V-ing form
couldn't I puncture? couldn't you puncture? couldn't she puncture? couldn't we puncture? couldn't you puncture? couldn't they puncture?	couldn't I be puncturing? couldn't you be puncturing? couldn't she be puncturing? couldn't we be puncturing? couldn't you be puncturing? couldn't they be puncturing?
Perfect	V-ing perfect
couldn't I have punctured? couldn't you have punctured? couldn't she have punctured? couldn't we have punctured? couldn't you have punctured? couldn't they have punctured?	couldn't I have been puncturing? couldn't you have been puncturing? couldn't she have been puncturing? couldn't we have been puncturing? couldn't you have been puncturing? couldn't they have been puncturing?