I must refuel you must refuel he must refuel we must refuel you must refuel they must refuel
V-ing form
I must be refuelling you must be refuelling he must be refuelling we must be refuelling you must be refuelling they must be refuelling
Perfect
I must have refuelled you must have refuelled he must have refuelled we must have refuelled you must have refuelled they must have refuelled
V-ing perfect
I must have been refuelling you must have been refuelling he must have been refuelling we must have been refuelling you must have been refuelling they must have been refuelling
Negation
Simple form
I mustn't refuel you mustn't refuel he mustn't refuel we mustn't refuel you mustn't refuel they mustn't refuel
V-ing form
I mustn't be refuelling you mustn't be refuelling he mustn't be refuelling we mustn't be refuelling you mustn't be refuelling they mustn't be refuelling
Perfect
I mustn't have refuelled you mustn't have refuelled he mustn't have refuelled we mustn't have refuelled you mustn't have refuelled they mustn't have refuelled
V-ing perfect
I mustn't have been refuelling you mustn't have been refuelling he mustn't have been refuelling we mustn't have been refuelling you mustn't have been refuelling they mustn't have been refuelling
Interrogative form
Simple form
must I refuel? must you refuel? must he refuel? must we refuel? must you refuel? must they refuel?
V-ing form
must I be refuelling? must you be refuelling? must he be refuelling? must we be refuelling? must you be refuelling? must they be refuelling?
Perfect
must I have refuelled? must you have refuelled? must he have refuelled? must we have refuelled? must you have refuelled? must they have refuelled?
V-ing perfect
must I have been refuelling? must you have been refuelling? must he have been refuelling? must we have been refuelling? must you have been refuelling? must they have been refuelling?
Interro-negative form
Simple form
mustn't I refuel? mustn't you refuel? mustn't he refuel? mustn't we refuel? mustn't you refuel? mustn't they refuel?
V-ing form
mustn't I be refuelling? mustn't you be refuelling? mustn't he be refuelling? mustn't we be refuelling? mustn't you be refuelling? mustn't they be refuelling?
Perfect
mustn't I have refuelled? mustn't you have refuelled? mustn't he have refuelled? mustn't we have refuelled? mustn't you have refuelled? mustn't they have refuelled?
V-ing perfect
mustn't I have been refuelling? mustn't you have been refuelling? mustn't he have been refuelling? mustn't we have been refuelling? mustn't you have been refuelling? mustn't they have been refuelling?