I must refuel you must refuel she must refuel we must refuel you must refuel they must refuel
V-ing form
I must be refuelling you must be refuelling she must be refuelling we must be refuelling you must be refuelling they must be refuelling
Perfect
I must have refuelled you must have refuelled she 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 she 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 she 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 she 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 she 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 she 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 she refuel? must we refuel? must you refuel? must they refuel?
V-ing form
must I be refuelling? must you be refuelling? must she be refuelling? must we be refuelling? must you be refuelling? must they be refuelling?
Perfect
must I have refuelled? must you have refuelled? must she 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 she 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 she 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 she 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 she 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 she have been refuelling? mustn't we have been refuelling? mustn't you have been refuelling? mustn't they have been refuelling?