I could contrast you could contrast she could contrast we could contrast you could contrast they could contrast
V-ing form
I could be contrasting you could be contrasting she could be contrasting we could be contrasting you could be contrasting they could be contrasting
Perfect
I could have contrasted you could have contrasted she 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 she could have been contrasting we could have been contrasting you could have been contrasting they could have been contrasting
Negation
Simple form
I couldn't contrast you couldn't contrast she couldn't contrast we couldn't contrast you couldn't contrast they couldn't contrast
V-ing form
I couldn't be contrasting you couldn't be contrasting she couldn't be contrasting we couldn't be contrasting you couldn't be contrasting they couldn't be contrasting
Perfect
I couldn't have contrasted you couldn't have contrasted she couldn't have contrasted we couldn't have contrasted you couldn't have contrasted they couldn't have contrasted
V-ing perfect
I couldn't have been contrasting you couldn't have been contrasting she couldn't have been contrasting we couldn't have been contrasting you couldn't have been contrasting they couldn't have been contrasting
Interrogative form
Simple form
could I contrast? could you contrast? could she contrast? could we contrast? could you contrast? could they contrast?
V-ing form
could I be contrasting? could you be contrasting? could she be contrasting? could we be contrasting? could you be contrasting? could they be contrasting?
Perfect
could I have contrasted? could you have contrasted? could she 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 she have been contrasting? could we have been contrasting? could you have been contrasting? could they have been contrasting?
Interro-negative form
Simple form
couldn't I contrast? couldn't you contrast? couldn't she contrast? couldn't we contrast? couldn't you contrast? couldn't they contrast?
V-ing form
couldn't I be contrasting? couldn't you be contrasting? couldn't she be contrasting? couldn't we be contrasting? couldn't you be contrasting? couldn't they be contrasting?
Perfect
couldn't I have contrasted? couldn't you have contrasted? couldn't she have contrasted? couldn't we have contrasted? couldn't you have contrasted? couldn't they have contrasted?
V-ing perfect
couldn't I have been contrasting? couldn't you have been contrasting? couldn't she have been contrasting? couldn't we have been contrasting? couldn't you have been contrasting? couldn't they have been contrasting?