English verb conjugation
COULD SUFFIX

Regular verb: suffix - suffixed - suffixed

Affirmation

Simple form	V-ing form
I could suffix you could suffix he could suffix we could suffix you could suffix they could suffix	I could be suffixing you could be suffixing he could be suffixing we could be suffixing you could be suffixing they could be suffixing
Perfect	V-ing perfect
I could have suffixed you could have suffixed he could have suffixed we could have suffixed you could have suffixed they could have suffixed	I could have been suffixing you could have been suffixing he could have been suffixing we could have been suffixing you could have been suffixing they could have been suffixing

Negation

Simple form	V-ing form
I couldn't suffix you couldn't suffix he couldn't suffix we couldn't suffix you couldn't suffix they couldn't suffix	I couldn't be suffixing you couldn't be suffixing he couldn't be suffixing we couldn't be suffixing you couldn't be suffixing they couldn't be suffixing
Perfect	V-ing perfect
I couldn't have suffixed you couldn't have suffixed he couldn't have suffixed we couldn't have suffixed you couldn't have suffixed they couldn't have suffixed	I couldn't have been suffixing you couldn't have been suffixing he couldn't have been suffixing we couldn't have been suffixing you couldn't have been suffixing they couldn't have been suffixing

Interrogative form

Simple form	V-ing form
could I suffix? could you suffix? could he suffix? could we suffix? could you suffix? could they suffix?	could I be suffixing? could you be suffixing? could he be suffixing? could we be suffixing? could you be suffixing? could they be suffixing?
Perfect	V-ing perfect
could I have suffixed? could you have suffixed? could he have suffixed? could we have suffixed? could you have suffixed? could they have suffixed?	could I have been suffixing? could you have been suffixing? could he have been suffixing? could we have been suffixing? could you have been suffixing? could they have been suffixing?

Interro-negative form

Simple form	V-ing form
couldn't I suffix? couldn't you suffix? couldn't he suffix? couldn't we suffix? couldn't you suffix? couldn't they suffix?	couldn't I be suffixing? couldn't you be suffixing? couldn't he be suffixing? couldn't we be suffixing? couldn't you be suffixing? couldn't they be suffixing?
Perfect	V-ing perfect
couldn't I have suffixed? couldn't you have suffixed? couldn't he have suffixed? couldn't we have suffixed? couldn't you have suffixed? couldn't they have suffixed?	couldn't I have been suffixing? couldn't you have been suffixing? couldn't he have been suffixing? couldn't we have been suffixing? couldn't you have been suffixing? couldn't they have been suffixing?