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