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