You must think a computer is the best thing in the world, right? You must think it works at a super speed and can do everything? Well, it's not! In fact, the brain is much more powerful than any super computer! Think about when a glass is just about to fall off the table. Your brain controls everything that you need to do to save that glass from falling. First your eyes check out what's going on, then tell your brain, and your brain decides how quickly you need to react(反应), and then your muscles(肌肉) go into action. That is just from your brain. No computer could ever come close to that!
The brain weighs just 3 pounds, but it controls everything you do from thinking, learning, feeling even to breathing and your heart beating. Even though the brain is just 2% of your body weight, it uses around 20% of all your energy in your body. That is a lot for such a small organ(器官). There are about 100 billion tiny, tiny little cells(细胞) in your brain. There are so many that it would take you over 3,000 years to count them all!
Your brain stops growing when you're 18, but it actually keeps on developing and learning new things. So your parents are really super smart! You won't be able to fool them! Believe it or not, your brain NEVER stops working. Even during sleeping, the brain works for long-term memory establishment(建立). It is realized that the brain is the second organ in the body as the heart that never stops during human lives.
So everyone should be proud of such a gift of nature.