I can help you can help he can help we can help you can help they can help
V-ing form
I can be helping you can be helping he can be helping we can be helping you can be helping they can be helping
Perfect
I can have helped you can have helped he can have helped we can have helped you can have helped they can have helped
V-ing perfect
I can have been helping you can have been helping he can have been helping we can have been helping you can have been helping they can have been helping
Negation
Simple form
I cannot help you cannot help he cannot help we cannot help you cannot help they cannot help
V-ing form
I cannot be helping you cannot be helping he cannot be helping we cannot be helping you cannot be helping they cannot be helping
Perfect
I cannot have helped you cannot have helped he cannot have helped we cannot have helped you cannot have helped they cannot have helped
V-ing perfect
I cannot have been helping you cannot have been helping he cannot have been helping we cannot have been helping you cannot have been helping they cannot have been helping
Interrogative form
Simple form
can I help? can you help? can he help? can we help? can you help? can they help?
V-ing form
can I be helping? can you be helping? can he be helping? can we be helping? can you be helping? can they be helping?
Perfect
can I have helped? can you have helped? can he have helped? can we have helped? can you have helped? can they have helped?
V-ing perfect
can I have been helping? can you have been helping? can he have been helping? can we have been helping? can you have been helping? can they have been helping?
Interro-negative form
Simple form
can I not help? can you not help? can he not help? can we not help? can you not help? can they not help?
V-ing form
can I not be helping? can you not be helping? can he not be helping? can we not be helping? can you not be helping? can they not be helping?
Perfect
can I not have helped? can you not have helped? can he not have helped? can we not have helped? can you not have helped? can they not have helped?
V-ing perfect
can I not have been helping? can you not have been helping? can he not have been helping? can we not have been helping? can you not have been helping? can they not have been helping?