I could dry you could dry she could dry we could dry you could dry they could dry
V-ing form
I could be drying you could be drying she could be drying we could be drying you could be drying they could be drying
Perfect
I could have dried you could have dried she 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 she could have been drying we could have been drying you could have been drying they could have been drying
Negation
Simple form
I couldn't dry you couldn't dry she couldn't dry we couldn't dry you couldn't dry they couldn't dry
V-ing form
I couldn't be drying you couldn't be drying she couldn't be drying we couldn't be drying you couldn't be drying they couldn't be drying
Perfect
I couldn't have dried you couldn't have dried she couldn't have dried we couldn't have dried you couldn't have dried they couldn't have dried
V-ing perfect
I couldn't have been drying you couldn't have been drying she couldn't have been drying we couldn't have been drying you couldn't have been drying they couldn't have been drying
Interrogative form
Simple form
could I dry? could you dry? could she dry? could we dry? could you dry? could they dry?
V-ing form
could I be drying? could you be drying? could she be drying? could we be drying? could you be drying? could they be drying?
Perfect
could I have dried? could you have dried? could she 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 she have been drying? could we have been drying? could you have been drying? could they have been drying?
Interro-negative form
Simple form
couldn't I dry? couldn't you dry? couldn't she dry? couldn't we dry? couldn't you dry? couldn't they dry?
V-ing form
couldn't I be drying? couldn't you be drying? couldn't she be drying? couldn't we be drying? couldn't you be drying? couldn't they be drying?
Perfect
couldn't I have dried? couldn't you have dried? couldn't she have dried? couldn't we have dried? couldn't you have dried? couldn't they have dried?
V-ing perfect
couldn't I have been drying? couldn't you have been drying? couldn't she have been drying? couldn't we have been drying? couldn't you have been drying? couldn't they have been drying?