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 couldn't sugar you couldn't sugar he couldn't sugar we couldn't sugar you couldn't sugar they couldn't sugar
V-ing form
I couldn't be sugaring you couldn't be sugaring he couldn't be sugaring we couldn't be sugaring you couldn't be sugaring they couldn't be sugaring
Perfect
I couldn't have sugared you couldn't have sugared he couldn't have sugared we couldn't have sugared you couldn't have sugared they couldn't have sugared
V-ing perfect
I couldn't have been sugaring you couldn't have been sugaring he couldn't have been sugaring we couldn't have been sugaring you couldn't have been sugaring they couldn't 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
couldn't I sugar? couldn't you sugar? couldn't he sugar? couldn't we sugar? couldn't you sugar? couldn't they sugar?
V-ing form
couldn't I be sugaring? couldn't you be sugaring? couldn't he be sugaring? couldn't we be sugaring? couldn't you be sugaring? couldn't they be sugaring?
Perfect
couldn't I have sugared? couldn't you have sugared? couldn't he have sugared? couldn't we have sugared? couldn't you have sugared? couldn't they have sugared?
V-ing perfect
couldn't I have been sugaring? couldn't you have been sugaring? couldn't he have been sugaring? couldn't we have been sugaring? couldn't you have been sugaring? couldn't they have been sugaring?