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 couldn't crop you couldn't crop he couldn't crop we couldn't crop you couldn't crop they couldn't crop
V-ing form
I couldn't be cropping you couldn't be cropping he couldn't be cropping we couldn't be cropping you couldn't be cropping they couldn't be cropping
Perfect
I couldn't have cropped you couldn't have cropped he couldn't have cropped we couldn't have cropped you couldn't have cropped they couldn't have cropped
V-ing perfect
I couldn't have been cropping you couldn't have been cropping he couldn't have been cropping we couldn't have been cropping you couldn't have been cropping they couldn't 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
couldn't I crop? couldn't you crop? couldn't he crop? couldn't we crop? couldn't you crop? couldn't they crop?
V-ing form
couldn't I be cropping? couldn't you be cropping? couldn't he be cropping? couldn't we be cropping? couldn't you be cropping? couldn't they be cropping?
Perfect
couldn't I have cropped? couldn't you have cropped? couldn't he have cropped? couldn't we have cropped? couldn't you have cropped? couldn't they have cropped?
V-ing perfect
couldn't I have been cropping? couldn't you have been cropping? couldn't he have been cropping? couldn't we have been cropping? couldn't you have been cropping? couldn't they have been cropping?