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 must not invest you must not invest she must not invest we must not invest you must not invest they must not invest
V-ing form
I must not be investing you must not be investing she must not be investing we must not be investing you must not be investing they must not be investing
Perfect
I must not have invested you must not have invested she must not have invested we must not have invested you must not have invested they must not have invested
V-ing perfect
I must not have been investing you must not have been investing she must not have been investing we must not have been investing you must not have been investing they must not 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
must I not invest? must you not invest? must she not invest? must we not invest? must you not invest? must they not invest?
V-ing form
must I not be investing? must you not be investing? must she not be investing? must we not be investing? must you not be investing? must they not be investing?
Perfect
must I not have invested? must you not have invested? must she not have invested? must we not have invested? must you not have invested? must they not have invested?
V-ing perfect
must I not have been investing? must you not have been investing? must she not have been investing? must we not have been investing? must you not have been investing? must they not have been investing?