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