1 . There’s a song in your head. You keep hearing it repeatedly. You can’t make it stop, and it’s driving you crazy! Has this happened to you? Maybe you have suffered from an earworm, which is a memory of a song.

Earworms are common. A study showed that 90 percent of people experience them. Why do we get earworms? According to neurologist Oliver Sacks, music affects us whether we pay attention to it or not. We’re surrounded by music all the time in our everyday lives. Sacks wonders if there is a higher incidence of earworms today because of all this music in our environment.

Research on the primary auditory cortex supports Sack’s ideas. The auditory cortex is the part of the brain that processes sound. It’s a short-term storage system for small amounts of auditory information. Some of this auditory information is forgotten, and some of it goes into long-term memory. However, songs appear to stay in the auditory cortex for a long time.

James Kellaris, a professor of marketing at the University of Cincinnati, thinks that only certain types of songs become earworms. These songs are repetitive, simple, and incongruous — something unexpected such as uneven rhythm. Your brain pays a lot of attention to a song like this, Kellaris says. Because it is repetitive and unusual, it stays longer in the auditory cortex. At that point, Kellaris believes, it becomes an annoying earworm.

Advertisers often use jingles — short songs that are easy to remember to promote sales. Advertisers want jingles to stick in people’s minds to keep them thinking about their products. It seems that advertisers have learned what Kellaris has found out in his research.

Is there any way to get rid of an earworm? Here are some tips Kellaris collected: replace the earworm song with another song, try to distract yourself by doing an intense activity such as exercising, or tell someone about your earworm. What if none of these strategies work? Then perhaps you should just sit back and try to enjoy the music in your head!

Whether to Study at Home or Abroad

“Radish knives” have become a hot-sale product in shops near schools. They are also a hot-sale product online. So far more than 400, 000 “radish knives”     1     (sell) online.

The rising popularity of these toys has raised worries among parents about their possibility to lead     2     violence (暴力) among teenagers, reported a local news outlet called Shunwang in Jinan, Shandong province.

A radish knife is a colorful plastic toy that looks just like a radish. It is made of plastic, and usually 5 centimeters in     3     (long). If a radish knife is pushed against the skin too hard, kids may get     4     (injure). Parents are confused about its popularity. “My daughter brought one home yesterday. She told me that it helped     5     (she) to reduce stress,” a parent told Shunwang.

“Playing with a toy knife may have     6     bad effect on children’s health,” said Yang Si-fan,     7     is an official at Chongqing Normal University. Children may pretend     8     (use)a toy knife to cut others after watching similar actions from movies and TV shows. Parents should be responsible for     9     (choose) suitable toys for their kids. If people find nearby stores selling these dangerous toys, they should report it to the government     10     (immediate). Toys like radish knives shouldn’t be allowed to be brought into schools.

5 . Gather together a couple of good friends and take a leisurely stroll through the streets — this is what many youngsters in China enjoy doing when they visit a new city.

To them, Citywalk means “roaming around the city” on foot. Participants can follow a distinctive urban route, soaking up the atmosphere, exploring old buildings, browsing boutique shops, sipping a cup of coffee, or indulging in authentic local snacks.

Citywalk can be a special guided trip for a small group of people, or simply a leisurely stroll for one or two to explore new areas, sticking to the key point: avoiding famous scenic spots and big crowds to gain a more inclusive experience of the places you visit. Besides interacting with a city, Citywalk provides young people with a new social scene, where they who share the same interests and ideas can easily make friends.

In China, the Citywalk trend is spreading from first-tier cities like Beijing and Shanghai to second and third-tier cities, encouraging more participants and event organizers to get involved. Some organizers invite folk culture researchers and enthusiasts to act as tour guides. Xiao Yiyi, a young entrepreneur in Changsha, recently launched six Citywalk routes in different cities on her social media account, with the aim of providing experiences for visitors to “walk in open-air museums”. Her Changsha route features more offbeat sights like historical architecture from the 19th century, artsy old alleys, and even a stop-off to sample the local spicy crayfish specialty.

Even though Citywalk is a relatively new phenomenon, it is offering a positive change to urban travelers as they can better choose the experiences based on their interests and needs. At the same time, Citywalk represents an opportunity for tour guides and travel service providers to offer a more tailored, professional service to meet with ever-changing market demands.

8 . Caviar (鱼子酱) is typically associated with sturgeons swimming in the Caspian Sea, but the Mexican version is made from the tiny eggs of ahuautle, an insect also known as “bird fly”. For Juan, a farmer, cultivating and collecting the tiny insect eggs known as ahuautle is a way of life. “It means tradition,” said Juan, one of the only six people known to still harvest ahuautle. They fear they may be the last.

The painstaking collection of “Mexican caviar” is threatened by the drying out of Lake Texcoco, development around the lakeshore and decreasing interest in the ingredient among younger generations. The dish’s survival is seen as an example of “community resistance”, similar to the way in which inhabitants around Lake Texcoco have managed to preserve other traditions, festivals and ceremonies.

For Juan, it’s hard. Dressed in shorts and rubber boots, Juan walks with an effort through the calf-high waters to collect pine branches he has pushed into the muddy lakebed the week before. The branches serve as an anchor for the bird-fly bugs to deposit their eggs. After about two hours, Juan has gathered a pile of sticks covered with thousands of bird-fly eggs. He returns to the edge of the lake to lay the sticks out to dry in the sun, which can take several hours or days, depending on the weather.

“Eating this is like revisiting the past,” said restaurant owner Guerrero, 61. He says the flavor of the ahuautle reminds him of his childhood. But Guerrero acknowledges that “Mexican caviar” is at risk of disappearing because younger generations aren’t familiar with the dish, and ever-fewer people harvest it in the scarce remaining lakes where it is found.

Edday, an entomologist (昆虫学家), said there are more than 430 species of eatable insects in Mexico. He said native people living around the lakes adopted the insect eggs as a source of protein because prior to the Spanish conquest of 1521, they had few domesticated (驯养的) animals. But now, Edday said, the dish “is associated with the countryside, perhaps with poverty, as if it were an undesirable protein.”