must founder
Regular verb: founder - foundered- foundered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must founder
you must founder
he must founder
we must founder
you must founder
they must founder 	I must be foundering
you must be foundering
he must be foundering
we must be foundering
you must be foundering
they must be foundering	I must have foundered
you must have foundered
he must have foundered
we must have foundered
you must have foundered
they must have foundered	I must have been foundering
you must have been foundering
he must have been foundering
we must have been foundering
you must have been foundering
they must have been foundering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not founder
you must not founder
he must not founder
we must not founder
you must not founder
they must not founder 	I must not be foundering
you must not be foundering
he must not be foundering
we must not be foundering
you must not be foundering
they must not be foundering	I must not have foundered
you must not have foundered
he must not have foundered
we must not have foundered
you must not have foundered
they must not have foundered	I must not have been foundering
you must not have been foundering
he must not have been foundering
we must not have been foundering
you must not have been foundering
they must not have been foundering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I founder?
must you founder?
must he founder?
must we founder?
must you founder?
must they founder? 	must I be foundering?
must you be foundering?
must he be foundering?
must we be foundering?
must you be foundering?
must they be foundering? 	must I have foundered?
must you have foundered?
must he have foundered?
must we have foundered?
must you have foundered?
must they have foundered? 	must I have been foundering?
must you have been foundering?
must he have been foundering?
must we have been foundering?
must you have been foundering?
must they have been foundering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not founder?
must you not founder?
must he not founder?
must we not founder?
must you not founder?
must they not founder? 	must I not be foundering?
must you not be foundering?
must he not be foundering?
must we not be foundering?
must you not be foundering?
must they not be foundering? 	must I not have foundered?
must you not have foundered?
must he not have foundered?
must we not have foundered?
must you not have foundered?
must they not have foundered? 	must I not have been foundering?
must you not have been foundering?
must he not have been foundering?
must we not have been foundering?
must you not have been foundering?
must they not have been foundering?