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