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