I must skimp you must skimp he must skimp we must skimp you must skimp they must skimp
V-ing form
I must be skimping you must be skimping he must be skimping we must be skimping you must be skimping they must be skimping
Perfect
I must have skimped you must have skimped he must have skimped we must have skimped you must have skimped they must have skimped
V-ing perfect
I must have been skimping you must have been skimping he must have been skimping we must have been skimping you must have been skimping they must have been skimping
Negation
Simple form
I must not skimp you must not skimp he must not skimp we must not skimp you must not skimp they must not skimp
V-ing form
I must not be skimping you must not be skimping he must not be skimping we must not be skimping you must not be skimping they must not be skimping
Perfect
I must not have skimped you must not have skimped he must not have skimped we must not have skimped you must not have skimped they must not have skimped
V-ing perfect
I must not have been skimping you must not have been skimping he must not have been skimping we must not have been skimping you must not have been skimping they must not have been skimping
Interrogative form
Simple form
must I skimp? must you skimp? must he skimp? must we skimp? must you skimp? must they skimp?
V-ing form
must I be skimping? must you be skimping? must he be skimping? must we be skimping? must you be skimping? must they be skimping?
Perfect
must I have skimped? must you have skimped? must he have skimped? must we have skimped? must you have skimped? must they have skimped?
V-ing perfect
must I have been skimping? must you have been skimping? must he have been skimping? must we have been skimping? must you have been skimping? must they have been skimping?
Interro-negative form
Simple form
must I not skimp? must you not skimp? must he not skimp? must we not skimp? must you not skimp? must they not skimp?
V-ing form
must I not be skimping? must you not be skimping? must he not be skimping? must we not be skimping? must you not be skimping? must they not be skimping?
Perfect
must I not have skimped? must you not have skimped? must he not have skimped? must we not have skimped? must you not have skimped? must they not have skimped?
V-ing perfect
must I not have been skimping? must you not have been skimping? must he not have been skimping? must we not have been skimping? must you not have been skimping? must they not have been skimping?