I must harness you must harness she must harness we must harness you must harness they must harness
V-ing form
I must be harnessing you must be harnessing she must be harnessing we must be harnessing you must be harnessing they must be harnessing
Perfect
I must have harnessed you must have harnessed she must have harnessed we must have harnessed you must have harnessed they must have harnessed
V-ing perfect
I must have been harnessing you must have been harnessing she must have been harnessing we must have been harnessing you must have been harnessing they must have been harnessing
Negation
Simple form
I must not harness you must not harness she must not harness we must not harness you must not harness they must not harness
V-ing form
I must not be harnessing you must not be harnessing she must not be harnessing we must not be harnessing you must not be harnessing they must not be harnessing
Perfect
I must not have harnessed you must not have harnessed she must not have harnessed we must not have harnessed you must not have harnessed they must not have harnessed
V-ing perfect
I must not have been harnessing you must not have been harnessing she must not have been harnessing we must not have been harnessing you must not have been harnessing they must not have been harnessing
Interrogative form
Simple form
must I harness? must you harness? must she harness? must we harness? must you harness? must they harness?
V-ing form
must I be harnessing? must you be harnessing? must she be harnessing? must we be harnessing? must you be harnessing? must they be harnessing?
Perfect
must I have harnessed? must you have harnessed? must she have harnessed? must we have harnessed? must you have harnessed? must they have harnessed?
V-ing perfect
must I have been harnessing? must you have been harnessing? must she have been harnessing? must we have been harnessing? must you have been harnessing? must they have been harnessing?
Interro-negative form
Simple form
must I not harness? must you not harness? must she not harness? must we not harness? must you not harness? must they not harness?
V-ing form
must I not be harnessing? must you not be harnessing? must she not be harnessing? must we not be harnessing? must you not be harnessing? must they not be harnessing?
Perfect
must I not have harnessed? must you not have harnessed? must she not have harnessed? must we not have harnessed? must you not have harnessed? must they not have harnessed?
V-ing perfect
must I not have been harnessing? must you not have been harnessing? must she not have been harnessing? must we not have been harnessing? must you not have been harnessing? must they not have been harnessing?