must tough
Regular verb: tough - toughed- toughed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must tough
you must tough
he must tough
we must tough
you must tough
they must tough 	I must be toughing
you must be toughing
he must be toughing
we must be toughing
you must be toughing
they must be toughing	I must have toughed
you must have toughed
he must have toughed
we must have toughed
you must have toughed
they must have toughed	I must have been toughing
you must have been toughing
he must have been toughing
we must have been toughing
you must have been toughing
they must have been toughing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not tough
you must not tough
he must not tough
we must not tough
you must not tough
they must not tough 	I must not be toughing
you must not be toughing
he must not be toughing
we must not be toughing
you must not be toughing
they must not be toughing	I must not have toughed
you must not have toughed
he must not have toughed
we must not have toughed
you must not have toughed
they must not have toughed	I must not have been toughing
you must not have been toughing
he must not have been toughing
we must not have been toughing
you must not have been toughing
they must not have been toughing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I tough?
must you tough?
must he tough?
must we tough?
must you tough?
must they tough? 	must I be toughing?
must you be toughing?
must he be toughing?
must we be toughing?
must you be toughing?
must they be toughing? 	must I have toughed?
must you have toughed?
must he have toughed?
must we have toughed?
must you have toughed?
must they have toughed? 	must I have been toughing?
must you have been toughing?
must he have been toughing?
must we have been toughing?
must you have been toughing?
must they have been toughing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not tough?
must you not tough?
must he not tough?
must we not tough?
must you not tough?
must they not tough? 	must I not be toughing?
must you not be toughing?
must he not be toughing?
must we not be toughing?
must you not be toughing?
must they not be toughing? 	must I not have toughed?
must you not have toughed?
must he not have toughed?
must we not have toughed?
must you not have toughed?
must they not have toughed? 	must I not have been toughing?
must you not have been toughing?
must he not have been toughing?
must we not have been toughing?
must you not have been toughing?
must they not have been toughing?