recent, clear photo of yourself. A school picture works best. Write your name and the title of your drawing on the back of your artwork. We must receive all artwork by September 15, 2016.

How is the cover art chosen?

　　We will have an online voting in October 2016. The artwork that receives the most votes will be put on the cover.

What if I have questions?

Call the American Education Department at 800-638-8299.

29. What do we know about the American Kidney Fund?

A. It makes people pay attention to kidney disease.

B. It helps doctors to find ways to treat kidney disease.

C. It mainly tells people staying healthy is important.

D. It has a plan to train excellent young art lovers.

30. Who can be allowed to take part in the contest?

A. A 17-year-old girl who lives in the USA.

B. A student from England who has kidney disease.

C. A healthy boy who is good at drawing.

D. A 10-year-old American boy with kidney disease.

31. The first winner's artwork ______.

A. will appear twice on the calendar

B. will be sent to Washington, D.C.

C. will be on the cover of the 2017 calendar

D. will be chosen by the organizers of the contest

Since the 1970s, scientists have been searching for ways to link the brain with computers. Brain-computer interface (BCI) technology could help people with disabilities send orders to machines.

　　Recently, two researchers, Jose Millan and Michele Tavella from the Federal Polytechnic School in Lausanne, Switzerland, showed a small robotic wheelchair directed by a person's thoughts.

　　In the laboratory, Tavella operated the wheelchair just by thinking about moving his left or right hand. He could even talk as he watched the vehicle and guided it with his thoughts.

"Our brain has billions of nerve cells(神经细胞). These send signals through the spinal cord (脊髓) to the muscles to give us the ability to move. But spinal cord injuries or other conditions can prevent these weak electrical signals from reaching the muscles." Tavella says. "Our system allows disabled people to communicate with outside world and also to control devices."

　　The researchers designed a special cap for the user. This cap picks up the signals from the scalp (头皮) and sends them to a computer. The computer interprets the signals and gives orders to the wheelchair. The wheelchair also has two cameras that identify objects in its path. They help the computer react to orders from the brain.

Prof. Millan, the team leader, says scientists keep improving the computer