I could crop you could crop he could crop we could crop you could crop they could crop
V-ing form
I could be cropping you could be cropping he could be cropping we could be cropping you could be cropping they could be cropping
Perfect
I could have cropped you could have cropped he could have cropped we could have cropped you could have cropped they could have cropped
V-ing perfect
I could have been cropping you could have been cropping he could have been cropping we could have been cropping you could have been cropping they could have been cropping
Negation
Simple form
I could not crop you could not crop he could not crop we could not crop you could not crop they could not crop
V-ing form
I could not be cropping you could not be cropping he could not be cropping we could not be cropping you could not be cropping they could not be cropping
Perfect
I could not have cropped you could not have cropped he could not have cropped we could not have cropped you could not have cropped they could not have cropped
V-ing perfect
I could not have been cropping you could not have been cropping he could not have been cropping we could not have been cropping you could not have been cropping they could not have been cropping
Interrogative form
Simple form
could I crop? could you crop? could he crop? could we crop? could you crop? could they crop?
V-ing form
could I be cropping? could you be cropping? could he be cropping? could we be cropping? could you be cropping? could they be cropping?
Perfect
could I have cropped? could you have cropped? could he have cropped? could we have cropped? could you have cropped? could they have cropped?
V-ing perfect
could I have been cropping? could you have been cropping? could he have been cropping? could we have been cropping? could you have been cropping? could they have been cropping?
Interro-negative form
Simple form
could I not crop? could you not crop? could he not crop? could we not crop? could you not crop? could they not crop?
V-ing form
could I not be cropping? could you not be cropping? could he not be cropping? could we not be cropping? could you not be cropping? could they not be cropping?
Perfect
could I not have cropped? could you not have cropped? could he not have cropped? could we not have cropped? could you not have cropped? could they not have cropped?
V-ing perfect
could I not have been cropping? could you not have been cropping? could he not have been cropping? could we not have been cropping? could you not have been cropping? could they not have been cropping?