I must swirl you must swirl he must swirl we must swirl you must swirl they must swirl
V-ing form
I must be swirling you must be swirling he must be swirling we must be swirling you must be swirling they must be swirling
Perfect
I must have swirled you must have swirled he must have swirled we must have swirled you must have swirled they must have swirled
V-ing perfect
I must have been swirling you must have been swirling he must have been swirling we must have been swirling you must have been swirling they must have been swirling
Negation
Simple form
I mustn't swirl you mustn't swirl he mustn't swirl we mustn't swirl you mustn't swirl they mustn't swirl
V-ing form
I mustn't be swirling you mustn't be swirling he mustn't be swirling we mustn't be swirling you mustn't be swirling they mustn't be swirling
Perfect
I mustn't have swirled you mustn't have swirled he mustn't have swirled we mustn't have swirled you mustn't have swirled they mustn't have swirled
V-ing perfect
I mustn't have been swirling you mustn't have been swirling he mustn't have been swirling we mustn't have been swirling you mustn't have been swirling they mustn't have been swirling
Interrogative form
Simple form
must I swirl? must you swirl? must he swirl? must we swirl? must you swirl? must they swirl?
V-ing form
must I be swirling? must you be swirling? must he be swirling? must we be swirling? must you be swirling? must they be swirling?
Perfect
must I have swirled? must you have swirled? must he have swirled? must we have swirled? must you have swirled? must they have swirled?
V-ing perfect
must I have been swirling? must you have been swirling? must he have been swirling? must we have been swirling? must you have been swirling? must they have been swirling?
Interro-negative form
Simple form
mustn't I swirl? mustn't you swirl? mustn't he swirl? mustn't we swirl? mustn't you swirl? mustn't they swirl?
V-ing form
mustn't I be swirling? mustn't you be swirling? mustn't he be swirling? mustn't we be swirling? mustn't you be swirling? mustn't they be swirling?
Perfect
mustn't I have swirled? mustn't you have swirled? mustn't he have swirled? mustn't we have swirled? mustn't you have swirled? mustn't they have swirled?
V-ing perfect
mustn't I have been swirling? mustn't you have been swirling? mustn't he have been swirling? mustn't we have been swirling? mustn't you have been swirling? mustn't they have been swirling?