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