I could realise you could realise she could realise we could realise you could realise they could realise
V-ing form
I could be realising you could be realising she could be realising we could be realising you could be realising they could be realising
Perfect
I could have realised you could have realised she could have realised we could have realised you could have realised they could have realised
V-ing perfect
I could have been realising you could have been realising she could have been realising we could have been realising you could have been realising they could have been realising
Negation
Simple form
I couldn't realise you couldn't realise she couldn't realise we couldn't realise you couldn't realise they couldn't realise
V-ing form
I couldn't be realising you couldn't be realising she couldn't be realising we couldn't be realising you couldn't be realising they couldn't be realising
Perfect
I couldn't have realised you couldn't have realised she couldn't have realised we couldn't have realised you couldn't have realised they couldn't have realised
V-ing perfect
I couldn't have been realising you couldn't have been realising she couldn't have been realising we couldn't have been realising you couldn't have been realising they couldn't have been realising
Interrogative form
Simple form
could I realise? could you realise? could she realise? could we realise? could you realise? could they realise?
V-ing form
could I be realising? could you be realising? could she be realising? could we be realising? could you be realising? could they be realising?
Perfect
could I have realised? could you have realised? could she have realised? could we have realised? could you have realised? could they have realised?
V-ing perfect
could I have been realising? could you have been realising? could she have been realising? could we have been realising? could you have been realising? could they have been realising?
Interro-negative form
Simple form
couldn't I realise? couldn't you realise? couldn't she realise? couldn't we realise? couldn't you realise? couldn't they realise?
V-ing form
couldn't I be realising? couldn't you be realising? couldn't she be realising? couldn't we be realising? couldn't you be realising? couldn't they be realising?
Perfect
couldn't I have realised? couldn't you have realised? couldn't she have realised? couldn't we have realised? couldn't you have realised? couldn't they have realised?
V-ing perfect
couldn't I have been realising? couldn't you have been realising? couldn't she have been realising? couldn't we have been realising? couldn't you have been realising? couldn't they have been realising?