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