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