What are you doing right now? Yes, you are reading this page. That also means you're moving your
eyes. You're thinking. You're breathing. You're listening. Possibly you're shifting(变换) positions. You're
also feeling things—this book, your chair, emotions. What lets you do all these things at the same time?
Your brain.
Your brain is the control center of your body and mind. Without your brainyou can't do anything. Your brain has more than 100 billion nerve(神经) cells. Each nerve cell makes from 1,000 to 10,000
connections with other nerve cells. The nerve cells send impulses back and forth in your brain and to and
from every part of your body. After you reach the age of 20, though, your brain cells start to die. This is
common. However, if you suffer an illness, or injury, even more nerve cells die in your brain. When a
nerve cell dies, the thousands of connections it made with other nerve cells are lost.
Until recently, scientists believed that the brain did not replace its dead cells. New studies, however,
prove not. Scientists have found new nerve cells in a part of the brain called the hippocampus(海马区).
The hippocampus helps the brain form memories from new experiences.
The discovery of these new nerve cells is not a cure for anything yet. It gives hope, however, of a cure
for brain damage from such things as epilepsy(癫痫病), Lou Gehrig's disease, car accidents, and strokes. Someday scientists might be able to use the new cells to replace damaged brain cells. Such a cure,
however, may take about ten years to develop. So at the same time, use your head—protect it!
2. Nerve cells in the brain______.
A. send massages to every part of the body
B. make connections only to other cells in the brain
C. can cure Lou Gehrig's disease
D. are a person's memory
2. The last sentence of the passage suggests that people______.
A. should use their head by carefully thinking through situations
B. should be careful not to injure their brains
C. have a skull (头盖骨) that provides all the protection needed by the brain
D. would see a quick cure for brain disease
3. The author explains what the hippocampus is by ______.
A. telling its history
B. comparing it to other parts of the brain
C. telling how it got its name
D. explaining what it does
4. Nerve impulses are______.
A. cures
B. disorders
C. memories
D. messages