I could shill you could shill he could shill we could shill you could shill they could shill
V-ing form
I could be shilling you could be shilling he could be shilling we could be shilling you could be shilling they could be shilling
Perfect
I could have shilled you could have shilled he could have shilled we could have shilled you could have shilled they could have shilled
V-ing perfect
I could have been shilling you could have been shilling he could have been shilling we could have been shilling you could have been shilling they could have been shilling
Negation
Simple form
I could not shill you could not shill he could not shill we could not shill you could not shill they could not shill
V-ing form
I could not be shilling you could not be shilling he could not be shilling we could not be shilling you could not be shilling they could not be shilling
Perfect
I could not have shilled you could not have shilled he could not have shilled we could not have shilled you could not have shilled they could not have shilled
V-ing perfect
I could not have been shilling you could not have been shilling he could not have been shilling we could not have been shilling you could not have been shilling they could not have been shilling
Interrogative form
Simple form
could I shill? could you shill? could he shill? could we shill? could you shill? could they shill?
V-ing form
could I be shilling? could you be shilling? could he be shilling? could we be shilling? could you be shilling? could they be shilling?
Perfect
could I have shilled? could you have shilled? could he have shilled? could we have shilled? could you have shilled? could they have shilled?
V-ing perfect
could I have been shilling? could you have been shilling? could he have been shilling? could we have been shilling? could you have been shilling? could they have been shilling?
Interro-negative form
Simple form
could I not shill? could you not shill? could he not shill? could we not shill? could you not shill? could they not shill?
V-ing form
could I not be shilling? could you not be shilling? could he not be shilling? could we not be shilling? could you not be shilling? could they not be shilling?
Perfect
could I not have shilled? could you not have shilled? could he not have shilled? could we not have shilled? could you not have shilled? could they not have shilled?
V-ing perfect
could I not have been shilling? could you not have been shilling? could he not have been shilling? could we not have been shilling? could you not have been shilling? could they not have been shilling?