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