I could concretise you could concretise he could concretise we could concretise you could concretise they could concretise
V-ing form
I could be concretising you could be concretising he could be concretising we could be concretising you could be concretising they could be concretising
Perfect
I could have concretised you could have concretised he could have concretised we could have concretised you could have concretised they could have concretised
V-ing perfect
I could have been concretising you could have been concretising he could have been concretising we could have been concretising you could have been concretising they could have been concretising
Negation
Simple form
I could not concretise you could not concretise he could not concretise we could not concretise you could not concretise they could not concretise
V-ing form
I could not be concretising you could not be concretising he could not be concretising we could not be concretising you could not be concretising they could not be concretising
Perfect
I could not have concretised you could not have concretised he could not have concretised we could not have concretised you could not have concretised they could not have concretised
V-ing perfect
I could not have been concretising you could not have been concretising he could not have been concretising we could not have been concretising you could not have been concretising they could not have been concretising
Interrogative form
Simple form
could I concretise? could you concretise? could he concretise? could we concretise? could you concretise? could they concretise?
V-ing form
could I be concretising? could you be concretising? could he be concretising? could we be concretising? could you be concretising? could they be concretising?
Perfect
could I have concretised? could you have concretised? could he have concretised? could we have concretised? could you have concretised? could they have concretised?
V-ing perfect
could I have been concretising? could you have been concretising? could he have been concretising? could we have been concretising? could you have been concretising? could they have been concretising?
Interro-negative form
Simple form
could I not concretise? could you not concretise? could he not concretise? could we not concretise? could you not concretise? could they not concretise?
V-ing form
could I not be concretising? could you not be concretising? could he not be concretising? could we not be concretising? could you not be concretising? could they not be concretising?
Perfect
could I not have concretised? could you not have concretised? could he not have concretised? could we not have concretised? could you not have concretised? could they not have concretised?
V-ing perfect
could I not have been concretising? could you not have been concretising? could he not have been concretising? could we not have been concretising? could you not have been concretising? could they not have been concretising?