I could collar you could collar she could collar we could collar you could collar they could collar
V-ing form
I could be collaring you could be collaring she could be collaring we could be collaring you could be collaring they could be collaring
Perfect
I could have collared you could have collared she could have collared we could have collared you could have collared they could have collared
V-ing perfect
I could have been collaring you could have been collaring she could have been collaring we could have been collaring you could have been collaring they could have been collaring
Negation
Simple form
I could not collar you could not collar she could not collar we could not collar you could not collar they could not collar
V-ing form
I could not be collaring you could not be collaring she could not be collaring we could not be collaring you could not be collaring they could not be collaring
Perfect
I could not have collared you could not have collared she could not have collared we could not have collared you could not have collared they could not have collared
V-ing perfect
I could not have been collaring you could not have been collaring she could not have been collaring we could not have been collaring you could not have been collaring they could not have been collaring
Interrogative form
Simple form
could I collar? could you collar? could she collar? could we collar? could you collar? could they collar?
V-ing form
could I be collaring? could you be collaring? could she be collaring? could we be collaring? could you be collaring? could they be collaring?
Perfect
could I have collared? could you have collared? could she have collared? could we have collared? could you have collared? could they have collared?
V-ing perfect
could I have been collaring? could you have been collaring? could she have been collaring? could we have been collaring? could you have been collaring? could they have been collaring?
Interro-negative form
Simple form
could I not collar? could you not collar? could she not collar? could we not collar? could you not collar? could they not collar?
V-ing form
could I not be collaring? could you not be collaring? could she not be collaring? could we not be collaring? could you not be collaring? could they not be collaring?
Perfect
could I not have collared? could you not have collared? could she not have collared? could we not have collared? could you not have collared? could they not have collared?
V-ing perfect
could I not have been collaring? could you not have been collaring? could she not have been collaring? could we not have been collaring? could you not have been collaring? could they not have been collaring?