I could contrast you could contrast he could contrast we could contrast you could contrast they could contrast
V-ing form
I could be contrasting you could be contrasting he could be contrasting we could be contrasting you could be contrasting they could be contrasting
Perfect
I could have contrasted you could have contrasted he could have contrasted we could have contrasted you could have contrasted they could have contrasted
V-ing perfect
I could have been contrasting you could have been contrasting he could have been contrasting we could have been contrasting you could have been contrasting they could have been contrasting
Negation
Simple form
I could not contrast you could not contrast he could not contrast we could not contrast you could not contrast they could not contrast
V-ing form
I could not be contrasting you could not be contrasting he could not be contrasting we could not be contrasting you could not be contrasting they could not be contrasting
Perfect
I could not have contrasted you could not have contrasted he could not have contrasted we could not have contrasted you could not have contrasted they could not have contrasted
V-ing perfect
I could not have been contrasting you could not have been contrasting he could not have been contrasting we could not have been contrasting you could not have been contrasting they could not have been contrasting
Interrogative form
Simple form
could I contrast? could you contrast? could he contrast? could we contrast? could you contrast? could they contrast?
V-ing form
could I be contrasting? could you be contrasting? could he be contrasting? could we be contrasting? could you be contrasting? could they be contrasting?
Perfect
could I have contrasted? could you have contrasted? could he have contrasted? could we have contrasted? could you have contrasted? could they have contrasted?
V-ing perfect
could I have been contrasting? could you have been contrasting? could he have been contrasting? could we have been contrasting? could you have been contrasting? could they have been contrasting?
Interro-negative form
Simple form
could I not contrast? could you not contrast? could he not contrast? could we not contrast? could you not contrast? could they not contrast?
V-ing form
could I not be contrasting? could you not be contrasting? could he not be contrasting? could we not be contrasting? could you not be contrasting? could they not be contrasting?
Perfect
could I not have contrasted? could you not have contrasted? could he not have contrasted? could we not have contrasted? could you not have contrasted? could they not have contrasted?
V-ing perfect
could I not have been contrasting? could you not have been contrasting? could he not have been contrasting? could we not have been contrasting? could you not have been contrasting? could they not have been contrasting?