English verb conjugation
COULD LOCK

Regular verb: lock - locked - locked

Affirmation

Simple form	V-ing form
I could lock you could lock he could lock we could lock you could lock they could lock	I could be locking you could be locking he could be locking we could be locking you could be locking they could be locking
Perfect	V-ing perfect
I could have locked you could have locked he could have locked we could have locked you could have locked they could have locked	I could have been locking you could have been locking he could have been locking we could have been locking you could have been locking they could have been locking

Negation

Simple form	V-ing form
I could not lock you could not lock he could not lock we could not lock you could not lock they could not lock	I could not be locking you could not be locking he could not be locking we could not be locking you could not be locking they could not be locking
Perfect	V-ing perfect
I could not have locked you could not have locked he could not have locked we could not have locked you could not have locked they could not have locked	I could not have been locking you could not have been locking he could not have been locking we could not have been locking you could not have been locking they could not have been locking

Interrogative form

Simple form	V-ing form
could I lock? could you lock? could he lock? could we lock? could you lock? could they lock?	could I be locking? could you be locking? could he be locking? could we be locking? could you be locking? could they be locking?
Perfect	V-ing perfect
could I have locked? could you have locked? could he have locked? could we have locked? could you have locked? could they have locked?	could I have been locking? could you have been locking? could he have been locking? could we have been locking? could you have been locking? could they have been locking?

Interro-negative form

Simple form	V-ing form
could I not lock? could you not lock? could he not lock? could we not lock? could you not lock? could they not lock?	could I not be locking? could you not be locking? could he not be locking? could we not be locking? could you not be locking? could they not be locking?
Perfect	V-ing perfect
could I not have locked? could you not have locked? could he not have locked? could we not have locked? could you not have locked? could they not have locked?	could I not have been locking? could you not have been locking? could he not have been locking? could we not have been locking? could you not have been locking? could they not have been locking?