When a person’s brain is hardened,
they do not know even if an entire age passes by. 
Having a hardened brain is like sleeping. 
Therefore, [people with a hardened brain] just let [things] pass by
without knowing for 5 years, 10 years and 20 years.
When a person’s brain is hardened,
they do not know even if an entire age passes by. 
Having a hardened brain is like sleeping. 
Therefore, [people with a hardened brain] just let [things] pass by
without knowing for 5 years, 10 years and 20 years.