must strengthen
Verbo regolare: strengthen - strengthened- strengthened

Affermazione 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
I must strengthen
you must strengthen
he must strengthen
we must strengthen
you must strengthen
they must strengthen 	I must be strengthening
you must be strengthening
he must be strengthening
we must be strengthening
you must be strengthening
they must be strengthening	I must have strengthened
you must have strengthened
he must have strengthened
we must have strengthened
you must have strengthened
they must have strengthened	I must have been strengthening
you must have been strengthening
he must have been strengthening
we must have been strengthening
you must have been strengthening
they must have been strengthening	

Negazione 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
I must not strengthen
you must not strengthen
he must not strengthen
we must not strengthen
you must not strengthen
they must not strengthen 	I must not be strengthening
you must not be strengthening
he must not be strengthening
we must not be strengthening
you must not be strengthening
they must not be strengthening	I must not have strengthened
you must not have strengthened
he must not have strengthened
we must not have strengthened
you must not have strengthened
they must not have strengthened	I must not have been strengthening
you must not have been strengthening
he must not have been strengthening
we must not have been strengthening
you must not have been strengthening
they must not have been strengthening	

Forma interrogativa 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
must I strengthen?
must you strengthen?
must he strengthen?
must we strengthen?
must you strengthen?
must they strengthen? 	must I be strengthening?
must you be strengthening?
must he be strengthening?
must we be strengthening?
must you be strengthening?
must they be strengthening? 	must I have strengthened?
must you have strengthened?
must he have strengthened?
must we have strengthened?
must you have strengthened?
must they have strengthened? 	must I have been strengthening?
must you have been strengthening?
must he have been strengthening?
must we have been strengthening?
must you have been strengthening?
must they have been strengthening? 	

Forma interro-negativa 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
must I not strengthen?
must you not strengthen?
must he not strengthen?
must we not strengthen?
must you not strengthen?
must they not strengthen? 	must I not be strengthening?
must you not be strengthening?
must he not be strengthening?
must we not be strengthening?
must you not be strengthening?
must they not be strengthening? 	must I not have strengthened?
must you not have strengthened?
must he not have strengthened?
must we not have strengthened?
must you not have strengthened?
must they not have strengthened? 	must I not have been strengthening?
must you not have been strengthening?
must he not have been strengthening?
must we not have been strengthening?
must you not have been strengthening?
must they not have been strengthening?