I could stimulate you could stimulate he could stimulate we could stimulate you could stimulate they could stimulate
V-ing form
I could be stimulating you could be stimulating he could be stimulating we could be stimulating you could be stimulating they could be stimulating
Perfect
I could have stimulated you could have stimulated he could have stimulated we could have stimulated you could have stimulated they could have stimulated
V-ing perfect
I could have been stimulating you could have been stimulating he could have been stimulating we could have been stimulating you could have been stimulating they could have been stimulating
Negation
Simple form
I could not stimulate you could not stimulate he could not stimulate we could not stimulate you could not stimulate they could not stimulate
V-ing form
I could not be stimulating you could not be stimulating he could not be stimulating we could not be stimulating you could not be stimulating they could not be stimulating
Perfect
I could not have stimulated you could not have stimulated he could not have stimulated we could not have stimulated you could not have stimulated they could not have stimulated
V-ing perfect
I could not have been stimulating you could not have been stimulating he could not have been stimulating we could not have been stimulating you could not have been stimulating they could not have been stimulating
Interrogative form
Simple form
could I stimulate? could you stimulate? could he stimulate? could we stimulate? could you stimulate? could they stimulate?
V-ing form
could I be stimulating? could you be stimulating? could he be stimulating? could we be stimulating? could you be stimulating? could they be stimulating?
Perfect
could I have stimulated? could you have stimulated? could he have stimulated? could we have stimulated? could you have stimulated? could they have stimulated?
V-ing perfect
could I have been stimulating? could you have been stimulating? could he have been stimulating? could we have been stimulating? could you have been stimulating? could they have been stimulating?
Interro-negative form
Simple form
could I not stimulate? could you not stimulate? could he not stimulate? could we not stimulate? could you not stimulate? could they not stimulate?
V-ing form
could I not be stimulating? could you not be stimulating? could he not be stimulating? could we not be stimulating? could you not be stimulating? could they not be stimulating?
Perfect
could I not have stimulated? could you not have stimulated? could he not have stimulated? could we not have stimulated? could you not have stimulated? could they not have stimulated?
V-ing perfect
could I not have been stimulating? could you not have been stimulating? could he not have been stimulating? could we not have been stimulating? could you not have been stimulating? could they not have been stimulating?