C. Asking for a correct answer. D. Redoing the typing twelve hours later.

26. What does the underlined word it in Para. 2 refer to?

A. Correcting the mistakes. B. Typing the French translation.

　　C. Typing the Swahili words. D. Showing the Swahili word on the screen.

27. Compared to the wake group , those in the sleep group .

A. typed more quickly B. made fewer translation mistakes.

　　C. learned with more effort. D. learned all the word- pairs.

　　C

　　At some point in life, many people suffer a mental problem. While most people get over it, for others it doesn't go away easily.

　　The World Health Organization (WHO) says that about 20 percent of children and teenagers across the globe suffer from mental illness. It's thought that the number of children and teenagers with mental illness around the world will increase by half by 2020. It will become one of the main causes of disease, disabilities and even death.

　　The reason for mental problems among young people may be the increasing pressure in life. Study and relationships have always caused huge stresses for school children. For instance, they experience school bullying（欺凌）and academic pressure.

　　In China, the picture isn't bright, either. About 30 million Chinese children and teenagers under the age of 17, or 10 percent of children and teenagers in China, have a mental health challenge, reported China Daily.

　　Also, according to China Daily, Chinese people don't seek help with their mental problems. They fear that others will think less of them if they admit that they are in trouble. Many Chinese people are ashamed of their mental problems and mental illness is taboo（禁忌）in any Chinese families.

　　In the UK, over three-quarters of young people believe their mental health problems have a social shame and a quarter of young UK people wouldn't ask for help if they developed a mental problem.

　　Young people who don't seek help for their condition may be creating problems for themselves in the future. If you feel something is wrong within you - seek help.

Feeling down? Here are three things to try if you feel low.