【推荐1】Today, people all over the world are moving out of small villages, and they are moving to live in big noisy cities. This is the movement from the countries to the cities. It has been going on for over two hundred years.

In many countries, the main reason why people come to live in cities is work. After one or two large factories have been built in or near a town, people come to find work. And soon an industrial(工业的) area begins to grow. There is usually a living area nearby. The factory workers can live there. The families of these workers need schools, hospitals and shops. So more people come to live in the area to provide these services and so a city grows.

In every big city in the world, there is a business area. There the big companies(公司) have their main offices. In the United States, this area is usually in the city centre. The people who work there often travel a long way to work each day. Many of them live outside the city. It is far away from the industrial area and the city centre.

What is the future of the big cities? Will they go on getting bigger and bigger? Perhaps(或许) not. Some big cities have become smaller in the last ten years. It is quite possible that one day we will see people moving out of the big cities and back into smaller towns and villages.

【推荐2】These days, short videos have gotten millions of views (关注) online. Many people create and share short videos on popular video apps like Douyin and Kuaishou. You can even add music and special effects (特效) to your videos. The videos are 15 seconds to a few minutes long. They show people doing activities like cooking, exercising and singing.

Teenagers especially enjoy these videos. More than 50 percent of students in Grade 7 and Grade 8 said they enjoyed watching these short videos. About 47 percent have posted their own videos, according to a recent report.

The videos let teenagers see funny and exciting things they wouldn't usually see. Many teens like to share the fun things they do with others as well. For example, a 12 year-old user named Xiao Qianyu has posted videos showing her learning jazz dance. This has won her many fans.

However, the videos can also cause trouble. Some students spend too much time watching them and not enough time studying. Some videos have vulgar content that is not good for teenagers.

To deal with this problem, Douyin added a new function (功能) in April, 2018. It locks the app if someone uses the app for over two hours a day. In the same month, the government asked companies to control these apps and get rid of bad videos.

A survey made by China Daily last year found that eight of 10 senior middle school students were nearsighted, compared with 71.6 percent in junior middle school, 36 percent in primary school and 14 percent of 6-year- olds in kindergarten. Overall, 53.6 percent were nearsighted.

The growing prevalence of myopia is not only a Chinese problem, but an especially East Asian one. In South Korea 96 percent of people (below the age 20) have myopia. In Singapore, the number is 82 percent. However, in the UK it is about 20-30 percent.

Some scientists think it is not good that so many students are nearsighted. It brings much trouble in their life, such as in the bathroom, the glasses people wear are easily covered by heat, which makes it impossible to see everything. What do you think if you put your glasses down before going to bed, you can’t find them in the morning?

Several factors have something to do with the high rate of nearsightedness in China’s children and teenagers, including lack of outdoor physical activities, lack of enough sleep due to heavy homework and too much use of electronics products.

Biologists compared Singaporeans living in Singapore to those living in Australia. They found that 29 percent of the Singaporean students had nearsightedness compared with just 3 percent in Sydney. The main reason was once again, time spent outside.

“The big difference was the Chinese children in Australia were outdoors lot more than their matched peers in Singapore,” says Ian Morgan, a retired biologist at Australian National University. “This was the only thing that fit with the huge difference in prevalence.”

A．

B．

C．

D．