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