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