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