I must refract you must refract he must refract we must refract you must refract they must refract
V-ing form
I must be refracting you must be refracting he must be refracting we must be refracting you must be refracting they must be refracting
Perfect
I must have refracted you must have refracted he must have refracted we must have refracted you must have refracted they must have refracted
V-ing perfect
I must have been refracting you must have been refracting he must have been refracting we must have been refracting you must have been refracting they must have been refracting
Negation
Simple form
I must not refract you must not refract he must not refract we must not refract you must not refract they must not refract
V-ing form
I must not be refracting you must not be refracting he must not be refracting we must not be refracting you must not be refracting they must not be refracting
Perfect
I must not have refracted you must not have refracted he must not have refracted we must not have refracted you must not have refracted they must not have refracted
V-ing perfect
I must not have been refracting you must not have been refracting he must not have been refracting we must not have been refracting you must not have been refracting they must not have been refracting
Interrogative form
Simple form
must I refract? must you refract? must he refract? must we refract? must you refract? must they refract?
V-ing form
must I be refracting? must you be refracting? must he be refracting? must we be refracting? must you be refracting? must they be refracting?
Perfect
must I have refracted? must you have refracted? must he have refracted? must we have refracted? must you have refracted? must they have refracted?
V-ing perfect
must I have been refracting? must you have been refracting? must he have been refracting? must we have been refracting? must you have been refracting? must they have been refracting?
Interro-negative form
Simple form
must I not refract? must you not refract? must he not refract? must we not refract? must you not refract? must they not refract?
V-ing form
must I not be refracting? must you not be refracting? must he not be refracting? must we not be refracting? must you not be refracting? must they not be refracting?
Perfect
must I not have refracted? must you not have refracted? must he not have refracted? must we not have refracted? must you not have refracted? must they not have refracted?
V-ing perfect
must I not have been refracting? must you not have been refracting? must he not have been refracting? must we not have been refracting? must you not have been refracting? must they not have been refracting?