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