English verb conjugation
COULD PLAN

Regular verb: plan - planned - planned

Affirmation

Simple form	V-ing form
I could plan you could plan he could plan we could plan you could plan they could plan	I could be planning you could be planning he could be planning we could be planning you could be planning they could be planning
Perfect	V-ing perfect
I could have planned you could have planned he could have planned we could have planned you could have planned they could have planned	I could have been planning you could have been planning he could have been planning we could have been planning you could have been planning they could have been planning

Negation

Simple form	V-ing form
I could not plan you could not plan he could not plan we could not plan you could not plan they could not plan	I could not be planning you could not be planning he could not be planning we could not be planning you could not be planning they could not be planning
Perfect	V-ing perfect
I could not have planned you could not have planned he could not have planned we could not have planned you could not have planned they could not have planned	I could not have been planning you could not have been planning he could not have been planning we could not have been planning you could not have been planning they could not have been planning

Interrogative form

Simple form	V-ing form
could I plan? could you plan? could he plan? could we plan? could you plan? could they plan?	could I be planning? could you be planning? could he be planning? could we be planning? could you be planning? could they be planning?
Perfect	V-ing perfect
could I have planned? could you have planned? could he have planned? could we have planned? could you have planned? could they have planned?	could I have been planning? could you have been planning? could he have been planning? could we have been planning? could you have been planning? could they have been planning?

Interro-negative form

Simple form	V-ing form
could I not plan? could you not plan? could he not plan? could we not plan? could you not plan? could they not plan?	could I not be planning? could you not be planning? could he not be planning? could we not be planning? could you not be planning? could they not be planning?
Perfect	V-ing perfect
could I not have planned? could you not have planned? could he not have planned? could we not have planned? could you not have planned? could they not have planned?	could I not have been planning? could you not have been planning? could he not have been planning? could we not have been planning? could you not have been planning? could they not have been planning?