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