I must flush you must flush he must flush we must flush you must flush they must flush
V-ing form
I must be flushing you must be flushing he must be flushing we must be flushing you must be flushing they must be flushing
Perfect
I must have flushed you must have flushed he must have flushed we must have flushed you must have flushed they must have flushed
V-ing perfect
I must have been flushing you must have been flushing he must have been flushing we must have been flushing you must have been flushing they must have been flushing
Negation
Simple form
I must not flush you must not flush he must not flush we must not flush you must not flush they must not flush
V-ing form
I must not be flushing you must not be flushing he must not be flushing we must not be flushing you must not be flushing they must not be flushing
Perfect
I must not have flushed you must not have flushed he must not have flushed we must not have flushed you must not have flushed they must not have flushed
V-ing perfect
I must not have been flushing you must not have been flushing he must not have been flushing we must not have been flushing you must not have been flushing they must not have been flushing
Interrogative form
Simple form
must I flush? must you flush? must he flush? must we flush? must you flush? must they flush?
V-ing form
must I be flushing? must you be flushing? must he be flushing? must we be flushing? must you be flushing? must they be flushing?
Perfect
must I have flushed? must you have flushed? must he have flushed? must we have flushed? must you have flushed? must they have flushed?
V-ing perfect
must I have been flushing? must you have been flushing? must he have been flushing? must we have been flushing? must you have been flushing? must they have been flushing?
Interro-negative form
Simple form
must I not flush? must you not flush? must he not flush? must we not flush? must you not flush? must they not flush?
V-ing form
must I not be flushing? must you not be flushing? must he not be flushing? must we not be flushing? must you not be flushing? must they not be flushing?
Perfect
must I not have flushed? must you not have flushed? must he not have flushed? must we not have flushed? must you not have flushed? must they not have flushed?
V-ing perfect
must I not have been flushing? must you not have been flushing? must he not have been flushing? must we not have been flushing? must you not have been flushing? must they not have been flushing?