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