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