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