I must design you must design he must design we must design you must design they must design
V-ing form
I must be designing you must be designing he must be designing we must be designing you must be designing they must be designing
Perfect
I must have designed you must have designed he must have designed we must have designed you must have designed they must have designed
V-ing perfect
I must have been designing you must have been designing he must have been designing we must have been designing you must have been designing they must have been designing
Negation
Simple form
I must not design you must not design he must not design we must not design you must not design they must not design
V-ing form
I must not be designing you must not be designing he must not be designing we must not be designing you must not be designing they must not be designing
Perfect
I must not have designed you must not have designed he must not have designed we must not have designed you must not have designed they must not have designed
V-ing perfect
I must not have been designing you must not have been designing he must not have been designing we must not have been designing you must not have been designing they must not have been designing
Interrogative form
Simple form
must I design? must you design? must he design? must we design? must you design? must they design?
V-ing form
must I be designing? must you be designing? must he be designing? must we be designing? must you be designing? must they be designing?
Perfect
must I have designed? must you have designed? must he have designed? must we have designed? must you have designed? must they have designed?
V-ing perfect
must I have been designing? must you have been designing? must he have been designing? must we have been designing? must you have been designing? must they have been designing?
Interro-negative form
Simple form
must I not design? must you not design? must he not design? must we not design? must you not design? must they not design?
V-ing form
must I not be designing? must you not be designing? must he not be designing? must we not be designing? must you not be designing? must they not be designing?
Perfect
must I not have designed? must you not have designed? must he not have designed? must we not have designed? must you not have designed? must they not have designed?
V-ing perfect
must I not have been designing? must you not have been designing? must he not have been designing? must we not have been designing? must you not have been designing? must they not have been designing?