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 must not attain you must not attain he must not attain we must not attain you must not attain they must not attain
V-ing form
I must not be attaining you must not be attaining he must not be attaining we must not be attaining you must not be attaining they must not be attaining
Perfect
I must not have attained you must not have attained he must not have attained we must not have attained you must not have attained they must not have attained
V-ing perfect
I must not have been attaining you must not have been attaining he must not have been attaining we must not have been attaining you must not have been attaining they must not 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
must I not attain? must you not attain? must he not attain? must we not attain? must you not attain? must they not attain?
V-ing form
must I not be attaining? must you not be attaining? must he not be attaining? must we not be attaining? must you not be attaining? must they not be attaining?
Perfect
must I not have attained? must you not have attained? must he not have attained? must we not have attained? must you not have attained? must they not have attained?
V-ing perfect
must I not have been attaining? must you not have been attaining? must he not have been attaining? must we not have been attaining? must you not have been attaining? must they not have been attaining?