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