I can succumb you can succumb she can succumb we can succumb you can succumb they can succumb
V-ing form
I can be succumbing you can be succumbing she can be succumbing we can be succumbing you can be succumbing they can be succumbing
Perfect
I can have succumbed you can have succumbed she can have succumbed we can have succumbed you can have succumbed they can have succumbed
V-ing perfect
I can have been succumbing you can have been succumbing she can have been succumbing we can have been succumbing you can have been succumbing they can have been succumbing
Negation
Simple form
I cannot succumb you cannot succumb she cannot succumb we cannot succumb you cannot succumb they cannot succumb
V-ing form
I cannot be succumbing you cannot be succumbing she cannot be succumbing we cannot be succumbing you cannot be succumbing they cannot be succumbing
Perfect
I cannot have succumbed you cannot have succumbed she cannot have succumbed we cannot have succumbed you cannot have succumbed they cannot have succumbed
V-ing perfect
I cannot have been succumbing you cannot have been succumbing she cannot have been succumbing we cannot have been succumbing you cannot have been succumbing they cannot have been succumbing
Interrogative form
Simple form
can I succumb? can you succumb? can she succumb? can we succumb? can you succumb? can they succumb?
V-ing form
can I be succumbing? can you be succumbing? can she be succumbing? can we be succumbing? can you be succumbing? can they be succumbing?
Perfect
can I have succumbed? can you have succumbed? can she have succumbed? can we have succumbed? can you have succumbed? can they have succumbed?
V-ing perfect
can I have been succumbing? can you have been succumbing? can she have been succumbing? can we have been succumbing? can you have been succumbing? can they have been succumbing?
Interro-negative form
Simple form
can I not succumb? can you not succumb? can she not succumb? can we not succumb? can you not succumb? can they not succumb?
V-ing form
can I not be succumbing? can you not be succumbing? can she not be succumbing? can we not be succumbing? can you not be succumbing? can they not be succumbing?
Perfect
can I not have succumbed? can you not have succumbed? can she not have succumbed? can we not have succumbed? can you not have succumbed? can they not have succumbed?
V-ing perfect
can I not have been succumbing? can you not have been succumbing? can she not have been succumbing? can we not have been succumbing? can you not have been succumbing? can they not have been succumbing?