I could glide you could glide she could glide we could glide you could glide they could glide
V-ing form
I could be gliding you could be gliding she could be gliding we could be gliding you could be gliding they could be gliding
Perfect
I could have glided you could have glided she could have glided we could have glided you could have glided they could have glided
V-ing perfect
I could have been gliding you could have been gliding she could have been gliding we could have been gliding you could have been gliding they could have been gliding
Negation
Simple form
I could not glide you could not glide she could not glide we could not glide you could not glide they could not glide
V-ing form
I could not be gliding you could not be gliding she could not be gliding we could not be gliding you could not be gliding they could not be gliding
Perfect
I could not have glided you could not have glided she could not have glided we could not have glided you could not have glided they could not have glided
V-ing perfect
I could not have been gliding you could not have been gliding she could not have been gliding we could not have been gliding you could not have been gliding they could not have been gliding
Interrogative form
Simple form
could I glide? could you glide? could she glide? could we glide? could you glide? could they glide?
V-ing form
could I be gliding? could you be gliding? could she be gliding? could we be gliding? could you be gliding? could they be gliding?
Perfect
could I have glided? could you have glided? could she have glided? could we have glided? could you have glided? could they have glided?
V-ing perfect
could I have been gliding? could you have been gliding? could she have been gliding? could we have been gliding? could you have been gliding? could they have been gliding?
Interro-negative form
Simple form
could I not glide? could you not glide? could she not glide? could we not glide? could you not glide? could they not glide?
V-ing form
could I not be gliding? could you not be gliding? could she not be gliding? could we not be gliding? could you not be gliding? could they not be gliding?
Perfect
could I not have glided? could you not have glided? could she not have glided? could we not have glided? could you not have glided? could they not have glided?
V-ing perfect
could I not have been gliding? could you not have been gliding? could she not have been gliding? could we not have been gliding? could you not have been gliding? could they not have been gliding?