More than 60 years after scientists made big discoveries about the structure of DNA, 20 students at US Coretta Scott King Young Women’s Leadership Academy gained insight（了解）into some of the molecular（分子的）mysteries that make them who they are.

Last fall, while studying life sciences, the girls sent samples（样本）of their DNA off to Living DNA, a DNA testing company. The test results became known last week and they left a big impression on the students, who were able to make real-world connections to topics they have been studying all semester long, including genotypes（基因型）.

“Students were able to maturely（成熟地）look at their results and apply what they learned in science. It’s about bringing learning to life,” said Laura Pena, the STEM program teacher.

For most of the girls, the DNA test was their ancestry（血统）. Sitting with her mom, Amariah Caudle, 15, looked with her mouth wide open at the charts showing her results. She was surprised that her European ancestry was only 13 percent. Her mother, Janell Caudle, was surprised it was that high.

“I didn’t think a trace（痕迹）would show up in her,” she said. “After many generations, this is still showing up in our bloodline（血统）. I was shocked by the science of it all.”

DNA has a power to engage people, said Diahan Southard, Living DNA community manager. Southard believes the program gives students an understanding of DNA at an important moment, when they are still young enough to absorb lessons and change their values.

Elianed Guzman, 14, said she knew little about her family except that they were from Mexico. She described in her native Spanish how surprised she was to learn that she shared genetic DNA with people in China, Japan and Korea.

As the girls sat in small groups to examine their results, with reactions ranging from confusion to surprise, they began to understand what it all means.

“Now I know I have family from everywhere,” said Amariah.

The buses in Curitiba (库里蒂巴), a city in south Brazil, carry two million passengers a day—that’s 85% of the city’s population. You buy your ticket before you get on the bus. The price is the same wherever you’re going. No one in the city lives more than 400 meters from a bus stop. People don’t use their cars much in the city, so there’s less pollution.

Japanese bullet trains (子弹头列车) travel at up to 320 kilometers an hour. The 520-kilometer journey between Tokyo and Osaka (大阪), the world’s busiest high-speed line, takes just three and a half hours. It would take seven hours by car. Bullet trains are used by many local people. They’re popular with foreign tourists, too, because, as a tourist, you can buy a rail pass which gives you unlimited (无限制的) travel during your trip in Japan.

Copenhagen (哥本哈根) is known as “______”. A third of the people who live there go to work by bike. In fact, you see more bikes than cars in the city center. There are 350 kilometers of cycle paths (道路). You don’t even need to have your own bike, you can use a city bike, which is free.

A good way to travel in Singapore is by river taxi. It’s not expensive and you get a great view of the city from the river. River taxis are popular with local people, tourists and anyone who wants to get from A to B. Each taxi can carry up to 60 passengers.

【推荐1】Hong Kong is one of the world’s most beautiful and famous cities. It attracts thousands of visitors every day. Why is Hong Kong so popular?

Hong Kong has become a shopping kingdom for visitors. In Hong Kong’s famous shopping centers, you can see all kinds of famous shops and expensive restaurants and bars. There you will forget all but to spend money.

Bruce Lee, the Chinese kung fu star, died in 1973, at the age of 33. After forty years, he is still known as Hong Kong’s most famous movie star. In 2015,a statue (像) of Bruce was built for his fans, and it has become one of the most wonderful views in Hong Kong.

In Hong Kong, it’s always hot and wet except in winter. Hong Kong has a lot of great benches, but they are very crowded. If you’d like to stay far from the crowd, you can take a boat to Mui Wo on Lantau Island and then take a bus or taxi to Cheung Sha Beach. It is one of Hong Kong’s longest beaches. There you can enjoy yourself.

【推荐3】Like you and your pet dog, plants are living things: they eat, drink, and grow. Unlike you and your dog, they can’t run away, use fists or teeth, or hide under the covers when they're threatened. But they can fight back.

Why would a plant need to fight back? To avoid being eaten, of course! Plants have several ways of protecting themselves. A plant can grow in a hidden or hard-to-get-to place. Think of plants you’ve seen growing on steep, rocky cliffs （悬崖）. Or, a plant could make only some parts of itself attractive to hungry insects and animals. For instance, if a plant produced really tasty leaves, herbivores （creatures that eat only plants） might eat the leaves instead of the seeds, which the plant needs for making more plants. Some plants have sharp or slippery （滑的）parts that discourage insects and other animals from getting too close, like the thorns （刺）on a rosebush.

But the most interesting way is that plants can produce chemicals. Plants take minerals from the soil and combine them into chemicals that do a lot of work. For example, plants produce chlorophyll （叶绿素）, which helps convert sunshine and water into the sugars that plants eat. They also produce chemicals to help protect themselves. One kind of tobacco plants releases a chemical into the air whenever small bugs begin to eat it. The chemical signals large bugs, saying "Dinner’s ready!" The big bugs come to eat the little ones and save the plant.

Most plants use chemicals in a more direct way against their enemies. In other words, plants make poison.

【推荐2】A European Union program is letting blind people experience famous paintings for the first time. It uses three dimensional (3-D) printing to recreate famous paintings so they can be touched.

One painting printed with the new technology is Gustav Klimt’s “The Kiss”. It is a popular attraction at the Belvedere Museum in Vienna, Austria. The painting shows a man and a woman standing in a field filled with flowers. They are wearing gold robes and have their arms around each other. The man leans down to kiss the woman.

Klimt finished the painting in 1908. Until now, people who had trouble seeing could not appreciate the artwork. But thanks to the reproduction, they can touch the piece and feel the ridges and depressions. Andreas Reichinger started making 3-D versions of artwork in 2010. He said this reproduction was his most difficult project because the couple’s robes are so detailed.

Dominika Raditsch is a blind museum visitor. She touched the reproduction. As she moved her hands around it she said, “Exactly, can you see these? There are so many details.” Raditsch said she can imagine what the original painting looks like when she touches the reproduction. “It’s somehow round. You can feel it. It comes with it. And in many places it’s so smooth. And then I think to myself: it probably shines too!” Raditsch said.

The Belvedere is not the only museum to have 3-D versions of its artwork. Some of the pieces at the Prado, in Madrid, Spain, have reproductions that can be touched. But the piece in Vienna has one special part: it is made with widely available 3-D printing technology. That means one day, blind art fans anywhere in the world could download the source files and print the reproductions themselves.