I could dry you could dry he could dry we could dry you could dry they could dry
V-ing form
I could be drying you could be drying he could be drying we could be drying you could be drying they could be drying
Perfect
I could have dried you could have dried he could have dried we could have dried you could have dried they could have dried
V-ing perfect
I could have been drying you could have been drying he could have been drying we could have been drying you could have been drying they could have been drying
Negation
Simple form
I could not dry you could not dry he could not dry we could not dry you could not dry they could not dry
V-ing form
I could not be drying you could not be drying he could not be drying we could not be drying you could not be drying they could not be drying
Perfect
I could not have dried you could not have dried he could not have dried we could not have dried you could not have dried they could not have dried
V-ing perfect
I could not have been drying you could not have been drying he could not have been drying we could not have been drying you could not have been drying they could not have been drying
Interrogative form
Simple form
could I dry? could you dry? could he dry? could we dry? could you dry? could they dry?
V-ing form
could I be drying? could you be drying? could he be drying? could we be drying? could you be drying? could they be drying?
Perfect
could I have dried? could you have dried? could he have dried? could we have dried? could you have dried? could they have dried?
V-ing perfect
could I have been drying? could you have been drying? could he have been drying? could we have been drying? could you have been drying? could they have been drying?
Interro-negative form
Simple form
could I not dry? could you not dry? could he not dry? could we not dry? could you not dry? could they not dry?
V-ing form
could I not be drying? could you not be drying? could he not be drying? could we not be drying? could you not be drying? could they not be drying?
Perfect
could I not have dried? could you not have dried? could he not have dried? could we not have dried? could you not have dried? could they not have dried?
V-ing perfect
could I not have been drying? could you not have been drying? could he not have been drying? could we not have been drying? could you not have been drying? could they not have been drying?