4 . On September 7, 1930, Yuan Longping was born in Beijing. Fluent in English, his mother often read Friedrich Nietzsche's works to him. Influenced by his mother, Yuan Longping liked English, geography and chemistry at school. After graduating from university, he became a teacher in the countryside of Hunan in 1953.

With lots of crop failures, nationwide hunger hit China in the 1960s, making many people live a bad life. Yuan was sad and felt he must do something. Since the climate in Hunan was not friendly to growing wheat. He decided to devote himself to studying how to increase the production of rice, a basic food for over 60 percent of Chinese people. From then on, he began a lifelong connection with rice.

Yuan Longping succeeded in growing the world's first high production hybrid rice (杂交水稻) variety in 1973, which could reach a yield of over 500 kg per more than 200 kg than before. For the next four decades, he continued to work on the research of hybrid rice. In 2020, hybrid rice developed by his team achieved 1,500 kg per mu in two growing seasons, a new world record.

Nowadays, the hybrid rice is grown in almost half of China's rice fields and its production accounts for 60 percent of the total rice production in China. The hybrid rice production is 20 percent more than the common kinds , the yearly increase of which feeds up to 100 million people.

In 2019, Yuan Longping, known as the “Father of hybrid rice”, was awarded with Medal of the Republic, China's highest honor.

Yuan Longping's biggest dream in life was to develop more hybrid rice varieties, which could be grown all over the world to help solve the global food problem. So far, the hybrid varieties he developed have been grown in over 40 countries, including the USA, Brazil and India.

5 . There are some bad cell phone habits that can have serious social, academic, health, and legal consequences. So, it is important and necessary to educate your teen about unhealthy habits. Here are some bad habits that teens need to stop:

Talk on the phone in quiet public areas. Make sure that your teen knows it is not OK to talk on the phone in theaters, libraries, waiting rooms, or other quiet public areas.    1    

Stare at their phones for hours. Many people--not just teens--are spending their days mindlessly scrolling through news feeds and social media accounts.     2     So set healthy limits on your teen’s cell phone use so he can enjoy real world experiences.

Make private conversations public. The whole world doesn’t need to know about the latest drama among your teen’s friends or the most recent family issue you’ve been experiencing.     3     Tell him to go to a private area if he must continue a phone conversation.

Take unsuitable pictures.    4     Unfortunately, that can often lead to taking selfies in dangerous places. Talk to your teen about the dangers of taking and sharing unsuitable photos.

    5     The rules about smartphone use in the classroom vary from school to school. Regardless of your school’s policies, cell phone use during school can serve as a major distraction. Talk to your teen about turning his phone off during the school day so he won’t use it.

6 . The Biggest Stadiums in the World

People have been pouring into stadiums since the days of ancient Greece. In around 80 A.D., the Romans built the Colosseum, which remains the world’s best known stadium and continues to inform contemporary design. Rome’s Colosseum was 157 feet tall and had 80 entrances, seating 50,000 people. However, that was small fry compared with the city’s Circus Maximus, which accommodated around 250,000 people.

These days, safety regulations-not to mention the modern sports fan’s desire for a good view and comfortable seat — tend to keep stadium capacities (容量) slightly lower. Even soccer fans tend to have a seat each; gone are the days of thousands standing to watch the match.

For the biggest stadiums in the world, we have used data supplied by the World Atlas list so far, which ranks them by their stated permanent capacity, as well as updated information from official stadium websites.

All these stadiums are still functional, still open and still hosting the biggest events in world sport.

·Rungrado 1st of May Stadium, Pyongyang D.P.R. Korea. Capacity: 150,000. Opened: May 1,1989.

·Michigan Stadium, Ann Arbor, Michigan, U. S. Capacity: 107,601. Opened: October 1, 1927.

·Beaver Stadium, State College, Pennsylvania, U. S. Capacity: 106,572. Opened: September 17, 1960.

·Ohio Stadium, Columbus, Ohio, U. S. Capacity: 104,944. Opened: October 7,1922.

·Kyle Field, College Station, Texas, U. S. Capacity: 102,512. Opened: September 24, 1927.

7 . Improvements to energy efficiency, such as LED lights, are seen by many authorities as a top priority for cutting carbon emissions. Yet a growing body of research suggests that a rebound effect could wipe out more than half of the savings from energy efficiency improvements, making the goals of the Paris Agreement on climate change even harder to hit.

A team led by Paul Brockway at the University of Leeds, UK, looked at the existing 33 studies on the impact of the rebound effect. First comes the direct rebound: for instance,when someone buys a more efficient car, they may take advantage of that by driving it further. Then comes the indirect rebound: fuel savings leave the owner with more money to spend elsewhere in the economy, consuming energy.

Although the 33 studies used different methods to model the rebound effect, they produced very consistent estimates of its impact, leading the team to conclude that the effect wipes out, on average, 63 percent of the anticipated energy savings.

“We're not saying energy efficiency doesn't work. What we're saying is rebound needs to be taken more seriously,” says Brockway.

The idea that increased efficiency may not deliver the hoped­for savings dates back to the Jevons paradox(悖论), named after the economist William Stanley Jevons, who, in 1865,observed that more efficient coal use led to more demand for coal.

If the rebound effect does prove to be as big as suggested, it means future global energy demand will be higher than expected and the world will need far more wind and solar power and carbon­capture technology than is currently being planned for.

But that doesn't mean nothing can be done to limit the rebound effect. One answer is to double down on energy efficiency and do twice as much to achieve the same effect.

8 . As an important piece of lifesaving equipment, a tall lifeguard chair is often seen on beaches, at lakes and community pools.    1    The design of the lifeguard chair offers several advantages that help prevent swimming accidents and increase the safety of swimmers.

A lifeguard chair is often tall, sometimes with a ladder attached to one side. The height of a life guard chair has two distinct advantages. First, it offers the lifeguard an unblocked view of the water he/she is guarding, allowing him/her to watch swimmers carefully for signs of danger.    2    

Some lifeguard chairs are quite basic, but others have several features to make the job of the lifeguard much easier.    3    As lifeguards often work long hours in sunny locations, a sunshade can prevent them from severe sunburn. A lifeguard chair may also have hooks and compartments (隔间) for lifesaving tools, making them easy to reach in an emergency.

    4    Nowadays resin (合成树脂) is also used, but metal is rarely used as it heats easily in the sun and can cause discomfort. Many lifeguard chairs are painted white to make them stand out from other objects around them.

A lifeguard chair is a very important piece of lifesaving equipment, but it’s not the only thing lifeguards need. There are many other devices used by lifeguards to do their job correctly.    5    They may also prepare a first aid box to help injured people as well as protect themselves from harm.