I could helicopter you could helicopter she could helicopter we could helicopter you could helicopter they could helicopter
V-ing form
I could be helicoptering you could be helicoptering she could be helicoptering we could be helicoptering you could be helicoptering they could be helicoptering
Perfect
I could have helicoptered you could have helicoptered she could have helicoptered we could have helicoptered you could have helicoptered they could have helicoptered
V-ing perfect
I could have been helicoptering you could have been helicoptering she could have been helicoptering we could have been helicoptering you could have been helicoptering they could have been helicoptering
Negation
Simple form
I could not helicopter you could not helicopter she could not helicopter we could not helicopter you could not helicopter they could not helicopter
V-ing form
I could not be helicoptering you could not be helicoptering she could not be helicoptering we could not be helicoptering you could not be helicoptering they could not be helicoptering
Perfect
I could not have helicoptered you could not have helicoptered she could not have helicoptered we could not have helicoptered you could not have helicoptered they could not have helicoptered
V-ing perfect
I could not have been helicoptering you could not have been helicoptering she could not have been helicoptering we could not have been helicoptering you could not have been helicoptering they could not have been helicoptering
Interrogative form
Simple form
could I helicopter? could you helicopter? could she helicopter? could we helicopter? could you helicopter? could they helicopter?
V-ing form
could I be helicoptering? could you be helicoptering? could she be helicoptering? could we be helicoptering? could you be helicoptering? could they be helicoptering?
Perfect
could I have helicoptered? could you have helicoptered? could she have helicoptered? could we have helicoptered? could you have helicoptered? could they have helicoptered?
V-ing perfect
could I have been helicoptering? could you have been helicoptering? could she have been helicoptering? could we have been helicoptering? could you have been helicoptering? could they have been helicoptering?
Interro-negative form
Simple form
could I not helicopter? could you not helicopter? could she not helicopter? could we not helicopter? could you not helicopter? could they not helicopter?
V-ing form
could I not be helicoptering? could you not be helicoptering? could she not be helicoptering? could we not be helicoptering? could you not be helicoptering? could they not be helicoptering?
Perfect
could I not have helicoptered? could you not have helicoptered? could she not have helicoptered? could we not have helicoptered? could you not have helicoptered? could they not have helicoptered?
V-ing perfect
could I not have been helicoptering? could you not have been helicoptering? could she not have been helicoptering? could we not have been helicoptering? could you not have been helicoptering? could they not have been helicoptering?