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