I could double-glaze you could double-glaze he could double-glaze we could double-glaze you could double-glaze they could double-glaze
V-ing form
I could be double-glazing you could be double-glazing he could be double-glazing we could be double-glazing you could be double-glazing they could be double-glazing
Perfect
I could have double-glazed you could have double-glazed he could have double-glazed we could have double-glazed you could have double-glazed they could have double-glazed
V-ing perfect
I could have been double-glazing you could have been double-glazing he could have been double-glazing we could have been double-glazing you could have been double-glazing they could have been double-glazing
Negation
Simple form
I could not double-glaze you could not double-glaze he could not double-glaze we could not double-glaze you could not double-glaze they could not double-glaze
V-ing form
I could not be double-glazing you could not be double-glazing he could not be double-glazing we could not be double-glazing you could not be double-glazing they could not be double-glazing
Perfect
I could not have double-glazed you could not have double-glazed he could not have double-glazed we could not have double-glazed you could not have double-glazed they could not have double-glazed
V-ing perfect
I could not have been double-glazing you could not have been double-glazing he could not have been double-glazing we could not have been double-glazing you could not have been double-glazing they could not have been double-glazing
Interrogative form
Simple form
could I double-glaze? could you double-glaze? could he double-glaze? could we double-glaze? could you double-glaze? could they double-glaze?
V-ing form
could I be double-glazing? could you be double-glazing? could he be double-glazing? could we be double-glazing? could you be double-glazing? could they be double-glazing?
Perfect
could I have double-glazed? could you have double-glazed? could he have double-glazed? could we have double-glazed? could you have double-glazed? could they have double-glazed?
V-ing perfect
could I have been double-glazing? could you have been double-glazing? could he have been double-glazing? could we have been double-glazing? could you have been double-glazing? could they have been double-glazing?
Interro-negative form
Simple form
could I not double-glaze? could you not double-glaze? could he not double-glaze? could we not double-glaze? could you not double-glaze? could they not double-glaze?
V-ing form
could I not be double-glazing? could you not be double-glazing? could he not be double-glazing? could we not be double-glazing? could you not be double-glazing? could they not be double-glazing?
Perfect
could I not have double-glazed? could you not have double-glazed? could he not have double-glazed? could we not have double-glazed? could you not have double-glazed? could they not have double-glazed?
V-ing perfect
could I not have been double-glazing? could you not have been double-glazing? could he not have been double-glazing? could we not have been double-glazing? could you not have been double-glazing? could they not have been double-glazing?