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