Human bodies are a miracle（奇迹）. Let's look at one example first.

How can you tell whether something is hot or cold? You touch it. There are things in your fingers that help you to know whether something is hot or cold. They're called nerves（神经）. You have them all over your body. Nerves react（反应） to things we touch and send messages（消息）through our bodies to our brain, telling us how something feels.

If you touched the edge of a knife, how would that feel? It would hurt. If you didn't have nerves, you would still bleed, but it wouldn't hurt. You wouldn't be able to feel it. So, why are nerves a good thing? We would hurt ourselves a lot more without them.

Imagine that you're making a snack in the kitchen. You put your hand down on the stove. After a minute or two, you see some smoke rising in the air. It's your hand! It's burning! If you had no nerves, you wouldn't be able to feel the heat from the stove. Then you would have to go to the hospital.

We had no nerves, the weather wouldn't affect（影响）us, or would it? If it were below 0℃, you wouldn't feel how cold it was. But if you went outside without protecting（保护）your body from the cold, you could get very sick or die. Nerves help us stay safe and healthy.

There are many other parts in our body that make us a miracle…

【小题1】Nerves work by ________________.

A．touching something	B．showing brains what to do
C．telling the hot from the cold	D．sending messages to the brain

【小题2】With the help of nerves, we _______________.

A．get hurt lesson often	B．don’t feel a lot of pain
C．don't bleed that much	D．stay away from hospitals

【小题3】The writer uses the examples of the knife and the stove to show ___________.

A．why nerves keep us from heat	B．how our fingers react to smoke
C．when people shouldn't use knives	D．what it is like if we have no nerves

【小题4】What might the writer write about next?

A．Ways to protect ourselves.	B．Different nerves in our body.
C．Other great parts in our body.	D．Miracles made by our nerves.