1 . Tsunami is a natural disaster, which is a Japanese word that means “sea wave”. A tsunami is a huge sea wave that forms mainly in the Pacific Ocean area. People die and property is destroyed when a tsunami hits land. What causes these dangerous sea waves? Sometimes, tsunamis are caused when earthquakes take place underwater. Then, water begins to move up and down from the top of the ocean right down to the bottom. Waves begin to form, and each wave is called a tsunami.

A tsunami is less than one meter high and can move at a speed of almost 800 kilometers per hour while it is far out in the ocean. But the tsunami rises much higher and moves more slowly as it comes closer to land.

The weather bureau (气象局) warns people over the radio and television when a tsunami is heading for land. These warnings have helped save many lives.

I was one of the people     1     work on Qinghai-Tibet Railway, which was completed by overcoming the most difficult engineering challenges to protect the delicate ecosystem.     2    (allow) animals to move safely and freely, thirty-three     3    (passage) have been built. To prevent damage to wetlands and grasslands, 675 bridges, which is about 160 kilometers in     4    (long), were built and 140,000 square meters of wetlands     5    (move) to protect its distinct ecosystem. Tanggula Station, which     6    (locate) at over 5,000 meters above sea level, is the highest railway station in the world. To keep us     7    (health), several oxygen-making stations were constructed. To protect Cuona Lake     8     construction waste, a twenty-kilometre wall was built. Thanks to     9     efforts, passengers, who have been attracted by the Qinghai-Tibet Plateau, have been enjoying these     10    (impress) landscape.

China has the world’s largest number of world natural heritage (遗产) sites. The country is now home     1     14 world natural heritage sites and four mixed sites,     2     are famous for both cultural and natural features, both leading the world in terms of quantity, the administration said. These heritage sites     3     (effective) protected China’s representative geological relics, mountains, forests and lakes, along with the rare and     4     (endanger) animal and plant species, the administration said Friday at     5     news meeting about cultural and natural heritage day, which falls on June 8 every year. In the past few years, the country     6     (increase) legal, and technological support of the protection of its world natural heritage, establishing a     7     (manage) system with Chinese characteristics. China’s world heritage has contributed to the country’ economic development     8     presented its image to the world. These areas have also played an important role in the protection of cultural relics, intangible cultural heritage and historic cities, towns and villages,     9     (bring) in over 14 billion yuan in average annual tourism income for     10     (local).

7 . Habitat loss, pesticides (农药) and climate change are threatening insect populations worldwide. In 2019, Biological Conservation reported that 40% of all insects species are declining (减少) globally and that a third of them are endangered.

And while it may sound nice to live in a world with fewer bad insects, environmental writer Oliver Milman says that human beings would be in big trouble without insects. That’s because insects play important roles in pollinating (给……授粉) plants we eat, breaking down waste in forest soil and forming the base of a food chain that other larger animals including- humans-rely upon.

“It would be an extremely terrible place to live in—and certainly not something we should ever aim for,” Milman says of an insect free existence. “You would certainly have mass starvation and social unrest…It’d be a place where there would be smelly waste and dead bodies everywhere because insects that break down those materials would be gone. ”

Milman charts the troubling decline of insects in his new book, The Insect Crisis: The Fall of the Tiny Empires That Run the World. He says that while it’s impossible to know exactly what’s happening with every insect species in the world, the overall trends are not good: The butterfly population in North America has declined quickly in the past 40 years, for example, and a U. N. assessment done in 2019 found that half a million insect species are under threat of extinction, some in the coming decades.

“The world, our surroundings, would be far quieter, far duller without insects,” he says. “When you start kind of digging down into these figures looking at the research, it’s clear that there’s something seriously wrong…There is a straight decline in most insect populations, and that spells major trouble for them but also for us.”

Chinese scientist Yuan Longping, globally known for developing the first hybrid rice strain in 1973 that served as a solution     1     worldwide hunger, passed away on Saturday at the age of 91.

The scientist spent over five decades researching and improving hybrid rice,     2    has reached its third generation, feeding     3    (approximate) one-fifth of the world's population with less than 9 percent of the world's total land. In China, the annual planting area of hybrid rice has topped 16 million hectares, or 57 percent of     4    total planting area of rice. Its growth area overseas has reached 8 million hectares. His more recent achievements included developing     5    (variety) of seawater rice, or saline-alkali tolerant rice. His team planned to use the rice     6    (transform) 6.7 million hectares of saline-alkali land in China over the next eight to 10 years.

Yuan once said he had two dreams—to “enjoy the cool under the rice crops taller than men” and that hybrid rice could be grown all over the world to help solve the global     7    (short) of food.

Yuan's lifelong devotion to reducing hunger is     8    has made him a national hero and household name in China is. In 1999, an asteroid (小行星)    9    (discover) by the National Astro-nomical Observatories was named after Yuan. In 2019, he     10    (award) the Medal of the Republic, China's highest state honor.