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