I could plan you could plan he could plan we could plan you could plan they could plan
V-ing form
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
I could have planned you could have planned he could have planned we could have planned you could have planned they could have planned
V-ing perfect
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
I couldn't plan you couldn't plan he couldn't plan we couldn't plan you couldn't plan they couldn't plan
V-ing form
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
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
V-ing perfect
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
could I plan? could you plan? could he plan? could we plan? could you plan? could they plan?
V-ing form
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
could I have planned? could you have planned? could he have planned? could we have planned? could you have planned? could they have planned?
V-ing perfect
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
couldn't I plan? couldn't you plan? couldn't he plan? couldn't we plan? couldn't you plan? couldn't they plan?
V-ing form
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
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?
V-ing perfect
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?