The human body has developed its millions of nerves to be highly aware of what goes on both inside and outside of it.This helps us adjust to the outside world.Without our nerves and our brain, 1 is a system of nerves,we couldn,t know what is happening. 2 we pay for our sensitivity(敏感度).We can feel pain 3 折磨) 4 (base)on the human body being open to pain.the slightest thing is wrong with any part of our body.The history of torture(