I must liaise you must liaise he must liaise we must liaise you must liaise they must liaise
V-ing form
I must be liaising you must be liaising he must be liaising we must be liaising you must be liaising they must be liaising
Perfect
I must have liaised you must have liaised he must have liaised we must have liaised you must have liaised they must have liaised
V-ing perfect
I must have been liaising you must have been liaising he must have been liaising we must have been liaising you must have been liaising they must have been liaising
Negation
Simple form
I must not liaise you must not liaise he must not liaise we must not liaise you must not liaise they must not liaise
V-ing form
I must not be liaising you must not be liaising he must not be liaising we must not be liaising you must not be liaising they must not be liaising
Perfect
I must not have liaised you must not have liaised he must not have liaised we must not have liaised you must not have liaised they must not have liaised
V-ing perfect
I must not have been liaising you must not have been liaising he must not have been liaising we must not have been liaising you must not have been liaising they must not have been liaising
Interrogative form
Simple form
must I liaise? must you liaise? must he liaise? must we liaise? must you liaise? must they liaise?
V-ing form
must I be liaising? must you be liaising? must he be liaising? must we be liaising? must you be liaising? must they be liaising?
Perfect
must I have liaised? must you have liaised? must he have liaised? must we have liaised? must you have liaised? must they have liaised?
V-ing perfect
must I have been liaising? must you have been liaising? must he have been liaising? must we have been liaising? must you have been liaising? must they have been liaising?
Interro-negative form
Simple form
must I not liaise? must you not liaise? must he not liaise? must we not liaise? must you not liaise? must they not liaise?
V-ing form
must I not be liaising? must you not be liaising? must he not be liaising? must we not be liaising? must you not be liaising? must they not be liaising?
Perfect
must I not have liaised? must you not have liaised? must he not have liaised? must we not have liaised? must you not have liaised? must they not have liaised?
V-ing perfect
must I not have been liaising? must you not have been liaising? must he not have been liaising? must we not have been liaising? must you not have been liaising? must they not have been liaising?