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