I could patent you could patent she could patent we could patent you could patent they could patent
V-ing form
I could be patenting you could be patenting she could be patenting we could be patenting you could be patenting they could be patenting
Perfect
I could have patented you could have patented she could have patented we could have patented you could have patented they could have patented
V-ing perfect
I could have been patenting you could have been patenting she could have been patenting we could have been patenting you could have been patenting they could have been patenting
Negation
Simple form
I could not patent you could not patent she could not patent we could not patent you could not patent they could not patent
V-ing form
I could not be patenting you could not be patenting she could not be patenting we could not be patenting you could not be patenting they could not be patenting
Perfect
I could not have patented you could not have patented she could not have patented we could not have patented you could not have patented they could not have patented
V-ing perfect
I could not have been patenting you could not have been patenting she could not have been patenting we could not have been patenting you could not have been patenting they could not have been patenting
Interrogative form
Simple form
could I patent? could you patent? could she patent? could we patent? could you patent? could they patent?
V-ing form
could I be patenting? could you be patenting? could she be patenting? could we be patenting? could you be patenting? could they be patenting?
Perfect
could I have patented? could you have patented? could she have patented? could we have patented? could you have patented? could they have patented?
V-ing perfect
could I have been patenting? could you have been patenting? could she have been patenting? could we have been patenting? could you have been patenting? could they have been patenting?
Interro-negative form
Simple form
could I not patent? could you not patent? could she not patent? could we not patent? could you not patent? could they not patent?
V-ing form
could I not be patenting? could you not be patenting? could she not be patenting? could we not be patenting? could you not be patenting? could they not be patenting?
Perfect
could I not have patented? could you not have patented? could she not have patented? could we not have patented? could you not have patented? could they not have patented?
V-ing perfect
could I not have been patenting? could you not have been patenting? could she not have been patenting? could we not have been patenting? could you not have been patenting? could they not have been patenting?