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 must not swirl you must not swirl he must not swirl we must not swirl you must not swirl they must not swirl
V-ing form
I must not be swirling you must not be swirling he must not be swirling we must not be swirling you must not be swirling they must not be swirling
Perfect
I must not have swirled you must not have swirled he must not have swirled we must not have swirled you must not have swirled they must not have swirled
V-ing perfect
I must not have been swirling you must not have been swirling he must not have been swirling we must not have been swirling you must not have been swirling they must not 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
must I not swirl? must you not swirl? must he not swirl? must we not swirl? must you not swirl? must they not swirl?
V-ing form
must I not be swirling? must you not be swirling? must he not be swirling? must we not be swirling? must you not be swirling? must they not be swirling?
Perfect
must I not have swirled? must you not have swirled? must he not have swirled? must we not have swirled? must you not have swirled? must they not have swirled?
V-ing perfect
must I not have been swirling? must you not have been swirling? must he not have been swirling? must we not have been swirling? must you not have been swirling? must they not have been swirling?