1 . When someone damages their backbone, the injury can leave them paralyzed (瘫痪). Now, scientists have given three paralyzed men the ability to walk again, thanks to an implanted device.

The human backbone, or spine, doesn’t just help us stand up straight. Inside is the spinal cord, which carries important information between the head and the lower part of the body. This information moves around as bursts of electricity traveling between the brain and the other parts of the body. When the spinal cord is hurt, this pathway gets damaged and they can’t move their legs.

Now scientists in Switzerland have given three paralyzed men the ability to walk again. To help them walk again, the men had surgery. A special device was placed directly on the lower part of their spinal cord, below their injury. This “implant” contained sixteen electrodes, which are small objects that electricity can pass through. The researchers made sure the electrodes were lined up with nerves that control the leg muscles. The scientists controlled the implants from a tablet computer.

The patient’s brains aren’t sending “walking” messages to their legs. Instead, the tablet tells the implant to send the walking messages. The researchers used computers to generate patterns of movement, like taking a step. The patient then uses the tablet to choose the pattern and the muscles move in the chosen way. Over time, the men were able to walk using a special walker with buttons to control each leg.

The solution isn’t perfect. It’s very expensive, it requires difficult surgery, and the patients can’t walk without the system. But the scientists are hopeful that in the future, this sort of technology will allow many paralyzed people to begin to walk again in just hours.

1. What's the main function of the spinal cord?

A．It serves as a message carrier.	B．It helps people stand up straight.
C．It takes control of the muscles.	D．It produces signals for movements.

2. What is the implanted device expected to do?

A．Activate the damaged nerves.	B．Identify the position of the injury.
C．Test the degree of the damage.	D．Bridge the nerve gap made by the injury.

3. What is Paragraph 4 mainly about?

A．How the surgery is performed.	B．How the device works on patients.
C．How the patients walk without aid.	D．How movement patterns are designed.

4. Which can be the best title of the text?

A．Damaged nerves recover after surgery.

B．Tablets are used in a medical treatment.

C．Implant helps the paralyzed walk again.

D．Scientists made a discovery on backbones.