must withstand
Irregular verb: withstand - withstood- withstood

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must withstand
you must withstand
he must withstand
we must withstand
you must withstand
they must withstand 	I must be withstanding
you must be withstanding
he must be withstanding
we must be withstanding
you must be withstanding
they must be withstanding	I must have withstood
you must have withstood
he must have withstood
we must have withstood
you must have withstood
they must have withstood	I must have been withstanding
you must have been withstanding
he must have been withstanding
we must have been withstanding
you must have been withstanding
they must have been withstanding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not withstand
you must not withstand
he must not withstand
we must not withstand
you must not withstand
they must not withstand 	I must not be withstanding
you must not be withstanding
he must not be withstanding
we must not be withstanding
you must not be withstanding
they must not be withstanding	I must not have withstood
you must not have withstood
he must not have withstood
we must not have withstood
you must not have withstood
they must not have withstood	I must not have been withstanding
you must not have been withstanding
he must not have been withstanding
we must not have been withstanding
you must not have been withstanding
they must not have been withstanding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I withstand?
must you withstand?
must he withstand?
must we withstand?
must you withstand?
must they withstand? 	must I be withstanding?
must you be withstanding?
must he be withstanding?
must we be withstanding?
must you be withstanding?
must they be withstanding? 	must I have withstood?
must you have withstood?
must he have withstood?
must we have withstood?
must you have withstood?
must they have withstood? 	must I have been withstanding?
must you have been withstanding?
must he have been withstanding?
must we have been withstanding?
must you have been withstanding?
must they have been withstanding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not withstand?
must you not withstand?
must he not withstand?
must we not withstand?
must you not withstand?
must they not withstand? 	must I not be withstanding?
must you not be withstanding?
must he not be withstanding?
must we not be withstanding?
must you not be withstanding?
must they not be withstanding? 	must I not have withstood?
must you not have withstood?
must he not have withstood?
must we not have withstood?
must you not have withstood?
must they not have withstood? 	must I not have been withstanding?
must you not have been withstanding?
must he not have been withstanding?
must we not have been withstanding?
must you not have been withstanding?
must they not have been withstanding?