I could glad you could glad he could glad we could glad you could glad they could glad
V-ing form
I could be glading you could be glading he could be glading we could be glading you could be glading they could be glading
Perfect
I could have gladed you could have gladed he could have gladed we could have gladed you could have gladed they could have gladed
V-ing perfect
I could have been glading you could have been glading he could have been glading we could have been glading you could have been glading they could have been glading
Negation
Simple form
I could not glad you could not glad he could not glad we could not glad you could not glad they could not glad
V-ing form
I could not be glading you could not be glading he could not be glading we could not be glading you could not be glading they could not be glading
Perfect
I could not have gladed you could not have gladed he could not have gladed we could not have gladed you could not have gladed they could not have gladed
V-ing perfect
I could not have been glading you could not have been glading he could not have been glading we could not have been glading you could not have been glading they could not have been glading
Interrogative form
Simple form
could I glad? could you glad? could he glad? could we glad? could you glad? could they glad?
V-ing form
could I be glading? could you be glading? could he be glading? could we be glading? could you be glading? could they be glading?
Perfect
could I have gladed? could you have gladed? could he have gladed? could we have gladed? could you have gladed? could they have gladed?
V-ing perfect
could I have been glading? could you have been glading? could he have been glading? could we have been glading? could you have been glading? could they have been glading?
Interro-negative form
Simple form
could I not glad? could you not glad? could he not glad? could we not glad? could you not glad? could they not glad?
V-ing form
could I not be glading? could you not be glading? could he not be glading? could we not be glading? could you not be glading? could they not be glading?
Perfect
could I not have gladed? could you not have gladed? could he not have gladed? could we not have gladed? could you not have gladed? could they not have gladed?
V-ing perfect
could I not have been glading? could you not have been glading? could he not have been glading? could we not have been glading? could you not have been glading? could they not have been glading?