I could trickle you could trickle she could trickle we could trickle you could trickle they could trickle
V-ing form
I could be trickling you could be trickling she could be trickling we could be trickling you could be trickling they could be trickling
Perfect
I could have trickled you could have trickled she could have trickled we could have trickled you could have trickled they could have trickled
V-ing perfect
I could have been trickling you could have been trickling she could have been trickling we could have been trickling you could have been trickling they could have been trickling
Negation
Simple form
I could not trickle you could not trickle she could not trickle we could not trickle you could not trickle they could not trickle
V-ing form
I could not be trickling you could not be trickling she could not be trickling we could not be trickling you could not be trickling they could not be trickling
Perfect
I could not have trickled you could not have trickled she could not have trickled we could not have trickled you could not have trickled they could not have trickled
V-ing perfect
I could not have been trickling you could not have been trickling she could not have been trickling we could not have been trickling you could not have been trickling they could not have been trickling
Interrogative form
Simple form
could I trickle? could you trickle? could she trickle? could we trickle? could you trickle? could they trickle?
V-ing form
could I be trickling? could you be trickling? could she be trickling? could we be trickling? could you be trickling? could they be trickling?
Perfect
could I have trickled? could you have trickled? could she have trickled? could we have trickled? could you have trickled? could they have trickled?
V-ing perfect
could I have been trickling? could you have been trickling? could she have been trickling? could we have been trickling? could you have been trickling? could they have been trickling?
Interro-negative form
Simple form
could I not trickle? could you not trickle? could she not trickle? could we not trickle? could you not trickle? could they not trickle?
V-ing form
could I not be trickling? could you not be trickling? could she not be trickling? could we not be trickling? could you not be trickling? could they not be trickling?
Perfect
could I not have trickled? could you not have trickled? could she not have trickled? could we not have trickled? could you not have trickled? could they not have trickled?
V-ing perfect
could I not have been trickling? could you not have been trickling? could she not have been trickling? could we not have been trickling? could you not have been trickling? could they not have been trickling?