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 couldn't plan you couldn't plan he couldn't plan we couldn't plan you couldn't plan they couldn't plan	I couldn't be planning you couldn't be planning he couldn't be planning we couldn't be planning you couldn't be planning they couldn't be planning
Perfect	V-ing perfect
I couldn't have planned you couldn't have planned he couldn't have planned we couldn't have planned you couldn't have planned they couldn't have planned	I couldn't have been planning you couldn't have been planning he couldn't have been planning we couldn't have been planning you couldn't have been planning they couldn't 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
couldn't I plan? couldn't you plan? couldn't he plan? couldn't we plan? couldn't you plan? couldn't they plan?	couldn't I be planning? couldn't you be planning? couldn't he be planning? couldn't we be planning? couldn't you be planning? couldn't they be planning?
Perfect	V-ing perfect
couldn't I have planned? couldn't you have planned? couldn't he have planned? couldn't we have planned? couldn't you have planned? couldn't they have planned?	couldn't I have been planning? couldn't you have been planning? couldn't he have been planning? couldn't we have been planning? couldn't you have been planning? couldn't they have been planning?