I could windmill you could windmill he could windmill we could windmill you could windmill they could windmill
V-ing form
I could be windmilling you could be windmilling he could be windmilling we could be windmilling you could be windmilling they could be windmilling
Perfect
I could have windmilled you could have windmilled he could have windmilled we could have windmilled you could have windmilled they could have windmilled
V-ing perfect
I could have been windmilling you could have been windmilling he could have been windmilling we could have been windmilling you could have been windmilling they could have been windmilling
Negation
Simple form
I could not windmill you could not windmill he could not windmill we could not windmill you could not windmill they could not windmill
V-ing form
I could not be windmilling you could not be windmilling he could not be windmilling we could not be windmilling you could not be windmilling they could not be windmilling
Perfect
I could not have windmilled you could not have windmilled he could not have windmilled we could not have windmilled you could not have windmilled they could not have windmilled
V-ing perfect
I could not have been windmilling you could not have been windmilling he could not have been windmilling we could not have been windmilling you could not have been windmilling they could not have been windmilling
Interrogative form
Simple form
could I windmill? could you windmill? could he windmill? could we windmill? could you windmill? could they windmill?
V-ing form
could I be windmilling? could you be windmilling? could he be windmilling? could we be windmilling? could you be windmilling? could they be windmilling?
Perfect
could I have windmilled? could you have windmilled? could he have windmilled? could we have windmilled? could you have windmilled? could they have windmilled?
V-ing perfect
could I have been windmilling? could you have been windmilling? could he have been windmilling? could we have been windmilling? could you have been windmilling? could they have been windmilling?
Interro-negative form
Simple form
could I not windmill? could you not windmill? could he not windmill? could we not windmill? could you not windmill? could they not windmill?
V-ing form
could I not be windmilling? could you not be windmilling? could he not be windmilling? could we not be windmilling? could you not be windmilling? could they not be windmilling?
Perfect
could I not have windmilled? could you not have windmilled? could he not have windmilled? could we not have windmilled? could you not have windmilled? could they not have windmilled?
V-ing perfect
could I not have been windmilling? could you not have been windmilling? could he not have been windmilling? could we not have been windmilling? could you not have been windmilling? could they not have been windmilling?