I could brad you could brad he could brad we could brad you could brad they could brad
V-ing form
I could be brading you could be brading he could be brading we could be brading you could be brading they could be brading
Perfect
I could have braded you could have braded he could have braded we could have braded you could have braded they could have braded
V-ing perfect
I could have been brading you could have been brading he could have been brading we could have been brading you could have been brading they could have been brading
Negation
Simple form
I could not brad you could not brad he could not brad we could not brad you could not brad they could not brad
V-ing form
I could not be brading you could not be brading he could not be brading we could not be brading you could not be brading they could not be brading
Perfect
I could not have braded you could not have braded he could not have braded we could not have braded you could not have braded they could not have braded
V-ing perfect
I could not have been brading you could not have been brading he could not have been brading we could not have been brading you could not have been brading they could not have been brading
Interrogative form
Simple form
could I brad? could you brad? could he brad? could we brad? could you brad? could they brad?
V-ing form
could I be brading? could you be brading? could he be brading? could we be brading? could you be brading? could they be brading?
Perfect
could I have braded? could you have braded? could he have braded? could we have braded? could you have braded? could they have braded?
V-ing perfect
could I have been brading? could you have been brading? could he have been brading? could we have been brading? could you have been brading? could they have been brading?
Interro-negative form
Simple form
could I not brad? could you not brad? could he not brad? could we not brad? could you not brad? could they not brad?
V-ing form
could I not be brading? could you not be brading? could he not be brading? could we not be brading? could you not be brading? could they not be brading?
Perfect
could I not have braded? could you not have braded? could he not have braded? could we not have braded? could you not have braded? could they not have braded?
V-ing perfect
could I not have been brading? could you not have been brading? could he not have been brading? could we not have been brading? could you not have been brading? could they not have been brading?