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