I could sugar you could sugar he could sugar we could sugar you could sugar they could sugar
V-ing form
I could be sugaring you could be sugaring he could be sugaring we could be sugaring you could be sugaring they could be sugaring
Perfect
I could have sugared you could have sugared he could have sugared we could have sugared you could have sugared they could have sugared
V-ing perfect
I could have been sugaring you could have been sugaring he could have been sugaring we could have been sugaring you could have been sugaring they could have been sugaring
Negation
Simple form
I could not sugar you could not sugar he could not sugar we could not sugar you could not sugar they could not sugar
V-ing form
I could not be sugaring you could not be sugaring he could not be sugaring we could not be sugaring you could not be sugaring they could not be sugaring
Perfect
I could not have sugared you could not have sugared he could not have sugared we could not have sugared you could not have sugared they could not have sugared
V-ing perfect
I could not have been sugaring you could not have been sugaring he could not have been sugaring we could not have been sugaring you could not have been sugaring they could not have been sugaring
Interrogative form
Simple form
could I sugar? could you sugar? could he sugar? could we sugar? could you sugar? could they sugar?
V-ing form
could I be sugaring? could you be sugaring? could he be sugaring? could we be sugaring? could you be sugaring? could they be sugaring?
Perfect
could I have sugared? could you have sugared? could he have sugared? could we have sugared? could you have sugared? could they have sugared?
V-ing perfect
could I have been sugaring? could you have been sugaring? could he have been sugaring? could we have been sugaring? could you have been sugaring? could they have been sugaring?
Interro-negative form
Simple form
could I not sugar? could you not sugar? could he not sugar? could we not sugar? could you not sugar? could they not sugar?
V-ing form
could I not be sugaring? could you not be sugaring? could he not be sugaring? could we not be sugaring? could you not be sugaring? could they not be sugaring?
Perfect
could I not have sugared? could you not have sugared? could he not have sugared? could we not have sugared? could you not have sugared? could they not have sugared?
V-ing perfect
could I not have been sugaring? could you not have been sugaring? could he not have been sugaring? could we not have been sugaring? could you not have been sugaring? could they not have been sugaring?