I must border you must border he must border we must border you must border they must border
V-ing form
I must be bordering you must be bordering he must be bordering we must be bordering you must be bordering they must be bordering
Perfect
I must have bordered you must have bordered he must have bordered we must have bordered you must have bordered they must have bordered
V-ing perfect
I must have been bordering you must have been bordering he must have been bordering we must have been bordering you must have been bordering they must have been bordering
Negation
Simple form
I must not border you must not border he must not border we must not border you must not border they must not border
V-ing form
I must not be bordering you must not be bordering he must not be bordering we must not be bordering you must not be bordering they must not be bordering
Perfect
I must not have bordered you must not have bordered he must not have bordered we must not have bordered you must not have bordered they must not have bordered
V-ing perfect
I must not have been bordering you must not have been bordering he must not have been bordering we must not have been bordering you must not have been bordering they must not have been bordering
Interrogative form
Simple form
must I border? must you border? must he border? must we border? must you border? must they border?
V-ing form
must I be bordering? must you be bordering? must he be bordering? must we be bordering? must you be bordering? must they be bordering?
Perfect
must I have bordered? must you have bordered? must he have bordered? must we have bordered? must you have bordered? must they have bordered?
V-ing perfect
must I have been bordering? must you have been bordering? must he have been bordering? must we have been bordering? must you have been bordering? must they have been bordering?
Interro-negative form
Simple form
must I not border? must you not border? must he not border? must we not border? must you not border? must they not border?
V-ing form
must I not be bordering? must you not be bordering? must he not be bordering? must we not be bordering? must you not be bordering? must they not be bordering?
Perfect
must I not have bordered? must you not have bordered? must he not have bordered? must we not have bordered? must you not have bordered? must they not have bordered?
V-ing perfect
must I not have been bordering? must you not have been bordering? must he not have been bordering? must we not have been bordering? must you not have been bordering? must they not have been bordering?