I could separate you could separate he could separate we could separate you could separate they could separate
V-ing form
I could be separating you could be separating he could be separating we could be separating you could be separating they could be separating
Perfect
I could have separated you could have separated he could have separated we could have separated you could have separated they could have separated
V-ing perfect
I could have been separating you could have been separating he could have been separating we could have been separating you could have been separating they could have been separating
Negation
Simple form
I couldn't separate you couldn't separate he couldn't separate we couldn't separate you couldn't separate they couldn't separate
V-ing form
I couldn't be separating you couldn't be separating he couldn't be separating we couldn't be separating you couldn't be separating they couldn't be separating
Perfect
I couldn't have separated you couldn't have separated he couldn't have separated we couldn't have separated you couldn't have separated they couldn't have separated
V-ing perfect
I couldn't have been separating you couldn't have been separating he couldn't have been separating we couldn't have been separating you couldn't have been separating they couldn't have been separating
Interrogative form
Simple form
could I separate? could you separate? could he separate? could we separate? could you separate? could they separate?
V-ing form
could I be separating? could you be separating? could he be separating? could we be separating? could you be separating? could they be separating?
Perfect
could I have separated? could you have separated? could he have separated? could we have separated? could you have separated? could they have separated?
V-ing perfect
could I have been separating? could you have been separating? could he have been separating? could we have been separating? could you have been separating? could they have been separating?
Interro-negative form
Simple form
couldn't I separate? couldn't you separate? couldn't he separate? couldn't we separate? couldn't you separate? couldn't they separate?
V-ing form
couldn't I be separating? couldn't you be separating? couldn't he be separating? couldn't we be separating? couldn't you be separating? couldn't they be separating?
Perfect
couldn't I have separated? couldn't you have separated? couldn't he have separated? couldn't we have separated? couldn't you have separated? couldn't they have separated?
V-ing perfect
couldn't I have been separating? couldn't you have been separating? couldn't he have been separating? couldn't we have been separating? couldn't you have been separating? couldn't they have been separating?