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 couldn't grease you couldn't grease he couldn't grease we couldn't grease you couldn't grease they couldn't grease
V-ing form
I couldn't be greasing you couldn't be greasing he couldn't be greasing we couldn't be greasing you couldn't be greasing they couldn't be greasing
Perfect
I couldn't have greased you couldn't have greased he couldn't have greased we couldn't have greased you couldn't have greased they couldn't have greased
V-ing perfect
I couldn't have been greasing you couldn't have been greasing he couldn't have been greasing we couldn't have been greasing you couldn't have been greasing they couldn't 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
couldn't I grease? couldn't you grease? couldn't he grease? couldn't we grease? couldn't you grease? couldn't they grease?
V-ing form
couldn't I be greasing? couldn't you be greasing? couldn't he be greasing? couldn't we be greasing? couldn't you be greasing? couldn't they be greasing?
Perfect
couldn't I have greased? couldn't you have greased? couldn't he have greased? couldn't we have greased? couldn't you have greased? couldn't they have greased?
V-ing perfect
couldn't I have been greasing? couldn't you have been greasing? couldn't he have been greasing? couldn't we have been greasing? couldn't you have been greasing? couldn't they have been greasing?