I can author you can author he can author we can author you can author they can author
V-ing form
I can be authoring you can be authoring he can be authoring we can be authoring you can be authoring they can be authoring
Perfect
I can have authored you can have authored he can have authored we can have authored you can have authored they can have authored
V-ing perfect
I can have been authoring you can have been authoring he can have been authoring we can have been authoring you can have been authoring they can have been authoring
Negation
Simple form
I cannot author you cannot author he cannot author we cannot author you cannot author they cannot author
V-ing form
I cannot be authoring you cannot be authoring he cannot be authoring we cannot be authoring you cannot be authoring they cannot be authoring
Perfect
I cannot have authored you cannot have authored he cannot have authored we cannot have authored you cannot have authored they cannot have authored
V-ing perfect
I cannot have been authoring you cannot have been authoring he cannot have been authoring we cannot have been authoring you cannot have been authoring they cannot have been authoring
Interrogative form
Simple form
can I author? can you author? can he author? can we author? can you author? can they author?
V-ing form
can I be authoring? can you be authoring? can he be authoring? can we be authoring? can you be authoring? can they be authoring?
Perfect
can I have authored? can you have authored? can he have authored? can we have authored? can you have authored? can they have authored?
V-ing perfect
can I have been authoring? can you have been authoring? can he have been authoring? can we have been authoring? can you have been authoring? can they have been authoring?
Interro-negative form
Simple form
can I not author? can you not author? can he not author? can we not author? can you not author? can they not author?
V-ing form
can I not be authoring? can you not be authoring? can he not be authoring? can we not be authoring? can you not be authoring? can they not be authoring?
Perfect
can I not have authored? can you not have authored? can he not have authored? can we not have authored? can you not have authored? can they not have authored?
V-ing perfect
can I not have been authoring? can you not have been authoring? can he not have been authoring? can we not have been authoring? can you not have been authoring? can they not have been authoring?