I could skimp you could skimp she could skimp we could skimp you could skimp they could skimp
V-ing form
I could be skimping you could be skimping she could be skimping we could be skimping you could be skimping they could be skimping
Perfect
I could have skimped you could have skimped she could have skimped we could have skimped you could have skimped they could have skimped
V-ing perfect
I could have been skimping you could have been skimping she could have been skimping we could have been skimping you could have been skimping they could have been skimping
Negation
Simple form
I could not skimp you could not skimp she could not skimp we could not skimp you could not skimp they could not skimp
V-ing form
I could not be skimping you could not be skimping she could not be skimping we could not be skimping you could not be skimping they could not be skimping
Perfect
I could not have skimped you could not have skimped she could not have skimped we could not have skimped you could not have skimped they could not have skimped
V-ing perfect
I could not have been skimping you could not have been skimping she could not have been skimping we could not have been skimping you could not have been skimping they could not have been skimping
Interrogative form
Simple form
could I skimp? could you skimp? could she skimp? could we skimp? could you skimp? could they skimp?
V-ing form
could I be skimping? could you be skimping? could she be skimping? could we be skimping? could you be skimping? could they be skimping?
Perfect
could I have skimped? could you have skimped? could she have skimped? could we have skimped? could you have skimped? could they have skimped?
V-ing perfect
could I have been skimping? could you have been skimping? could she have been skimping? could we have been skimping? could you have been skimping? could they have been skimping?
Interro-negative form
Simple form
could I not skimp? could you not skimp? could she not skimp? could we not skimp? could you not skimp? could they not skimp?
V-ing form
could I not be skimping? could you not be skimping? could she not be skimping? could we not be skimping? could you not be skimping? could they not be skimping?
Perfect
could I not have skimped? could you not have skimped? could she not have skimped? could we not have skimped? could you not have skimped? could they not have skimped?
V-ing perfect
could I not have been skimping? could you not have been skimping? could she not have been skimping? could we not have been skimping? could you not have been skimping? could they not have been skimping?