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