I must stall you must stall she must stall we must stall you must stall they must stall
V-ing form
I must be stalling you must be stalling she must be stalling we must be stalling you must be stalling they must be stalling
Perfect
I must have stalled you must have stalled she must have stalled we must have stalled you must have stalled they must have stalled
V-ing perfect
I must have been stalling you must have been stalling she must have been stalling we must have been stalling you must have been stalling they must have been stalling
Negation
Simple form
I mustn't stall you mustn't stall she mustn't stall we mustn't stall you mustn't stall they mustn't stall
V-ing form
I mustn't be stalling you mustn't be stalling she mustn't be stalling we mustn't be stalling you mustn't be stalling they mustn't be stalling
Perfect
I mustn't have stalled you mustn't have stalled she mustn't have stalled we mustn't have stalled you mustn't have stalled they mustn't have stalled
V-ing perfect
I mustn't have been stalling you mustn't have been stalling she mustn't have been stalling we mustn't have been stalling you mustn't have been stalling they mustn't have been stalling
Interrogative form
Simple form
must I stall? must you stall? must she stall? must we stall? must you stall? must they stall?
V-ing form
must I be stalling? must you be stalling? must she be stalling? must we be stalling? must you be stalling? must they be stalling?
Perfect
must I have stalled? must you have stalled? must she have stalled? must we have stalled? must you have stalled? must they have stalled?
V-ing perfect
must I have been stalling? must you have been stalling? must she have been stalling? must we have been stalling? must you have been stalling? must they have been stalling?
Interro-negative form
Simple form
mustn't I stall? mustn't you stall? mustn't she stall? mustn't we stall? mustn't you stall? mustn't they stall?
V-ing form
mustn't I be stalling? mustn't you be stalling? mustn't she be stalling? mustn't we be stalling? mustn't you be stalling? mustn't they be stalling?
Perfect
mustn't I have stalled? mustn't you have stalled? mustn't she have stalled? mustn't we have stalled? mustn't you have stalled? mustn't they have stalled?
V-ing perfect
mustn't I have been stalling? mustn't you have been stalling? mustn't she have been stalling? mustn't we have been stalling? mustn't you have been stalling? mustn't they have been stalling?