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