I must stair-step you must stair-step he must stair-step we must stair-step you must stair-step they must stair-step
V-ing form
I must be stair-steping you must be stair-steping he must be stair-steping we must be stair-steping you must be stair-steping they must be stair-steping
Perfect
I must have stair-steped you must have stair-steped he must have stair-steped we must have stair-steped you must have stair-steped they must have stair-steped
V-ing perfect
I must have been stair-steping you must have been stair-steping he must have been stair-steping we must have been stair-steping you must have been stair-steping they must have been stair-steping
Negation
Simple form
I must not stair-step you must not stair-step he must not stair-step we must not stair-step you must not stair-step they must not stair-step
V-ing form
I must not be stair-steping you must not be stair-steping he must not be stair-steping we must not be stair-steping you must not be stair-steping they must not be stair-steping
Perfect
I must not have stair-steped you must not have stair-steped he must not have stair-steped we must not have stair-steped you must not have stair-steped they must not have stair-steped
V-ing perfect
I must not have been stair-steping you must not have been stair-steping he must not have been stair-steping we must not have been stair-steping you must not have been stair-steping they must not have been stair-steping
Interrogative form
Simple form
must I stair-step? must you stair-step? must he stair-step? must we stair-step? must you stair-step? must they stair-step?
V-ing form
must I be stair-steping? must you be stair-steping? must he be stair-steping? must we be stair-steping? must you be stair-steping? must they be stair-steping?
Perfect
must I have stair-steped? must you have stair-steped? must he have stair-steped? must we have stair-steped? must you have stair-steped? must they have stair-steped?
V-ing perfect
must I have been stair-steping? must you have been stair-steping? must he have been stair-steping? must we have been stair-steping? must you have been stair-steping? must they have been stair-steping?
Interro-negative form
Simple form
must I not stair-step? must you not stair-step? must he not stair-step? must we not stair-step? must you not stair-step? must they not stair-step?
V-ing form
must I not be stair-steping? must you not be stair-steping? must he not be stair-steping? must we not be stair-steping? must you not be stair-steping? must they not be stair-steping?
Perfect
must I not have stair-steped? must you not have stair-steped? must he not have stair-steped? must we not have stair-steped? must you not have stair-steped? must they not have stair-steped?
V-ing perfect
must I not have been stair-steping? must you not have been stair-steping? must he not have been stair-steping? must we not have been stair-steping? must you not have been stair-steping? must they not have been stair-steping?