I could shallow you could shallow she could shallow we could shallow you could shallow they could shallow
V-ing form
I could be shallowing you could be shallowing she could be shallowing we could be shallowing you could be shallowing they could be shallowing
Perfect
I could have shallowed you could have shallowed she could have shallowed we could have shallowed you could have shallowed they could have shallowed
V-ing perfect
I could have been shallowing you could have been shallowing she could have been shallowing we could have been shallowing you could have been shallowing they could have been shallowing
Negation
Simple form
I could not shallow you could not shallow she could not shallow we could not shallow you could not shallow they could not shallow
V-ing form
I could not be shallowing you could not be shallowing she could not be shallowing we could not be shallowing you could not be shallowing they could not be shallowing
Perfect
I could not have shallowed you could not have shallowed she could not have shallowed we could not have shallowed you could not have shallowed they could not have shallowed
V-ing perfect
I could not have been shallowing you could not have been shallowing she could not have been shallowing we could not have been shallowing you could not have been shallowing they could not have been shallowing
Interrogative form
Simple form
could I shallow? could you shallow? could she shallow? could we shallow? could you shallow? could they shallow?
V-ing form
could I be shallowing? could you be shallowing? could she be shallowing? could we be shallowing? could you be shallowing? could they be shallowing?
Perfect
could I have shallowed? could you have shallowed? could she have shallowed? could we have shallowed? could you have shallowed? could they have shallowed?
V-ing perfect
could I have been shallowing? could you have been shallowing? could she have been shallowing? could we have been shallowing? could you have been shallowing? could they have been shallowing?
Interro-negative form
Simple form
could I not shallow? could you not shallow? could she not shallow? could we not shallow? could you not shallow? could they not shallow?
V-ing form
could I not be shallowing? could you not be shallowing? could she not be shallowing? could we not be shallowing? could you not be shallowing? could they not be shallowing?
Perfect
could I not have shallowed? could you not have shallowed? could she not have shallowed? could we not have shallowed? could you not have shallowed? could they not have shallowed?
V-ing perfect
could I not have been shallowing? could you not have been shallowing? could she not have been shallowing? could we not have been shallowing? could you not have been shallowing? could they not have been shallowing?