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