English verb conjugation
COULD SHEAF

Regular verb: sheaf - sheafed - sheafed

Affirmation

Simple form	V-ing form
I could sheaf you could sheaf he could sheaf we could sheaf you could sheaf they could sheaf	I could be sheafing you could be sheafing he could be sheafing we could be sheafing you could be sheafing they could be sheafing
Perfect	V-ing perfect
I could have sheafed you could have sheafed he could have sheafed we could have sheafed you could have sheafed they could have sheafed	I could have been sheafing you could have been sheafing he could have been sheafing we could have been sheafing you could have been sheafing they could have been sheafing

Negation

Simple form	V-ing form
I couldn't sheaf you couldn't sheaf he couldn't sheaf we couldn't sheaf you couldn't sheaf they couldn't sheaf	I couldn't be sheafing you couldn't be sheafing he couldn't be sheafing we couldn't be sheafing you couldn't be sheafing they couldn't be sheafing
Perfect	V-ing perfect
I couldn't have sheafed you couldn't have sheafed he couldn't have sheafed we couldn't have sheafed you couldn't have sheafed they couldn't have sheafed	I couldn't have been sheafing you couldn't have been sheafing he couldn't have been sheafing we couldn't have been sheafing you couldn't have been sheafing they couldn't have been sheafing

Interrogative form

Simple form	V-ing form
could I sheaf? could you sheaf? could he sheaf? could we sheaf? could you sheaf? could they sheaf?	could I be sheafing? could you be sheafing? could he be sheafing? could we be sheafing? could you be sheafing? could they be sheafing?
Perfect	V-ing perfect
could I have sheafed? could you have sheafed? could he have sheafed? could we have sheafed? could you have sheafed? could they have sheafed?	could I have been sheafing? could you have been sheafing? could he have been sheafing? could we have been sheafing? could you have been sheafing? could they have been sheafing?

Interro-negative form

Simple form	V-ing form
couldn't I sheaf? couldn't you sheaf? couldn't he sheaf? couldn't we sheaf? couldn't you sheaf? couldn't they sheaf?	couldn't I be sheafing? couldn't you be sheafing? couldn't he be sheafing? couldn't we be sheafing? couldn't you be sheafing? couldn't they be sheafing?
Perfect	V-ing perfect
couldn't I have sheafed? couldn't you have sheafed? couldn't he have sheafed? couldn't we have sheafed? couldn't you have sheafed? couldn't they have sheafed?	couldn't I have been sheafing? couldn't you have been sheafing? couldn't he have been sheafing? couldn't we have been sheafing? couldn't you have been sheafing? couldn't they have been sheafing?