I could grease you could grease he could grease we could grease you could grease they could grease
V-ing form
I could be greasing you could be greasing he could be greasing we could be greasing you could be greasing they could be greasing
Perfect
I could have greased you could have greased he could have greased we could have greased you could have greased they could have greased
V-ing perfect
I could have been greasing you could have been greasing he could have been greasing we could have been greasing you could have been greasing they could have been greasing
Negation
Simple form
I could not grease you could not grease he could not grease we could not grease you could not grease they could not grease
V-ing form
I could not be greasing you could not be greasing he could not be greasing we could not be greasing you could not be greasing they could not be greasing
Perfect
I could not have greased you could not have greased he could not have greased we could not have greased you could not have greased they could not have greased
V-ing perfect
I could not have been greasing you could not have been greasing he could not have been greasing we could not have been greasing you could not have been greasing they could not have been greasing
Interrogative form
Simple form
could I grease? could you grease? could he grease? could we grease? could you grease? could they grease?
V-ing form
could I be greasing? could you be greasing? could he be greasing? could we be greasing? could you be greasing? could they be greasing?
Perfect
could I have greased? could you have greased? could he have greased? could we have greased? could you have greased? could they have greased?
V-ing perfect
could I have been greasing? could you have been greasing? could he have been greasing? could we have been greasing? could you have been greasing? could they have been greasing?
Interro-negative form
Simple form
could I not grease? could you not grease? could he not grease? could we not grease? could you not grease? could they not grease?
V-ing form
could I not be greasing? could you not be greasing? could he not be greasing? could we not be greasing? could you not be greasing? could they not be greasing?
Perfect
could I not have greased? could you not have greased? could he not have greased? could we not have greased? could you not have greased? could they not have greased?
V-ing perfect
could I not have been greasing? could you not have been greasing? could he not have been greasing? could we not have been greasing? could you not have been greasing? could they not have been greasing?