Earthquakes are quite common. In fact, thousands of earthquakes are happening almost at every moment.     1    , most of them are too weak to feel. During a big earthquake, there is often a big noise first. Then the earth shakes     2     (terrible) and many houses fall down.

As one of the most deadly     3     (nature) disasters in the world, earthquakes often result     4     many people being injured or killed. In 2008, a strong earthquake     5     (strike) China’s Sichuan Province,     6     (kill) lots of people there.

Besides the great damage and deaths     7     (cause) by the earthquake, other accidents such as fires often follow. More buildings may be damaged and more     8     (injure) may be caused. For centuries, people have been making studies of earthquakes.     9     is said that about 2,000 years ago, for example, someone invented a machine     10     could find out the direction where the earthquake waves came.

First-time visitors to Chengdu may find it to be a city with rich cultural heritage. The emblem(标志)of a gold leaf,     1     (feature)four flying birds surrounding the sun, can be seen everywhere in the city. The emblem, which represents Chengdu,     2     (choose)as the symbol of China Cultural Heritage by the State Administration of Cultural Heritage in 2005.

After the discovery of the Sanxingdui Ruins in the city of Guanghan in 1929,     3     was believed to be one of Sichuan`s most important archaeological finds, a 3,000-year-old gold-leaf sunbird was unearthed at the Jinsha Ruins in 2001. In 2018, Chengdu made the decision     4     (become)a world cultural city. In recent years, Chengdu`s efforts to globalize have accelerated,     5     a series of major international cultural and sports activities have been held, laying the foundation for it to build itself into a world-famous tourist city.

Chengdu’s     6     (attract)range from giant pandas     7     the poetic legacy of the Du Fu Thatched Cottage.     8     (hide)in thick greenery, the Temple of Marquis Wu was built as     9     memorial hall in honor of Zhuge Liang and now China’s personification of loyalty and wisdom. The city also offers a museum including a cottage modelled after the poetic descriptions of Du Fu, one of the greatest poets     10     (historic)in China, emphasizing his influence on Chinese literature.

Strange things were happening in the countryside of northeastern Hebei. For several days, the water in the village wells rose and fell, rose and fell. There were deep cracks     1     appeared in the well walls. At least one well had some smelly gas     2     (come) out of it. Chickens and even pigs were too nervous     3     ( eat), and dogs refused to go inside buildings. Mice ran out of the fields looking for places to hide, and fish jumped out of the water. At about 3:00 a.m., on 28 July 1976, bright lights were seen in the sky outside the city of Tangshan and loud noises     4     (hear). But the city’s one million people were asleep as usual that night.

At 3:42 a. m., everything began to shake. It seemed as     5     the world were coming to an end! Eleven kilometres directly below the city, one of the most deadly     6     (earthquake) of the 20th century had begun, a quake that even caused damage more than 150 kilometres away in Beijing. Nearly one third of the whole nation felt it! A huge crack, eight kilometres     7     (length) and 30 metres wide, cut across houses, roads, and waterways. Hard hills of rock became rivers of dirt. In less than one minute, a large city lay     8     ruins. Two thirds of the people who lived there were dead or     9     (injure). Thousands of children were left without parents. The number of people who were killed or     10     (bad) injured in the quake was more than 400,000.

Some theme parks not only make people feel     1     (amaze) but also are educational. Take the Polynesian Cultural Center (PCC) in Hawaii for example. It not only shows visitors the Polynesian way of life but also     2     (protect) their skills and culture for the future. Polynesia is     3     name given to the groups of small islands that are spread about the Pacific Ocean.

The     4     (villager) from many island communities come to the Polynesian island villages to show visitors their styles of dress and different customs. They are the places     5     visitors can learn how the islanders make clothes from bark (树皮) and how the islanders climb very tall trees with their bare feet.

One of the important skills for Polynesians is boat-building. It allows the islanders     6     (explore) all the islands in the Polynesian Triangle.     7     (obvious), they were sea travellers in their history moving     8     island to island. They were     9     (confidence) of finding their way by     10     (use) the smell of the wind, the movements of the fish and seaweed, and the heights and directions of the waves.

Twin giant pandas have been born at a breeding (繁殖) center in southwestern China,    1    is a sign of progress for the endangered species as they struggle for survival due to occupation on their land by agriculture    2    industry.

The male and female baby pandas, born on Tuesday at the Qinling Panda Research Center in Shaanxi Province, are the second pair of twins born to    3     (they) mother, Qin Qin. She was also born at the center and    4     (previous) gave birth to twin females in 2020.

Chinese researchers for years have been working    5     (promote) the population of the animals, which reproduce rarely in the wild and rely    6    a diet of bamboo in the    7     (mountain) of southwestern China.

The efforts have paid off, with some captive-bred pandas being released into the wild. The population of wild pandas    8     (increase) over the past few years,    9     (reach) an estimated 1,800. About 500 others live in zoos and reserves, while the    10     (major) live in the mountainous, heavily forested province of Sichuan.

On February 16, 1861, a big earthquake struck Sumatra, an Indonesian island. The earthquake shook the western side of the island,     1     (cause ) a tsunami. That wall of water poured onto shore, destroying towns and taking thousands of    2     (life) .

Recently, though, a team of scientists discovered that another earthquake occurred before this deadly event. According to the record, that earthquake     3     (start) in 1829 and lasted for 32 years but no one felt even one shake. This kind of slow-moving earthquake    4     (call) “silent earthquakes” because no instrument can find them. Scientists have only begun discovering them because    5     the advances in GPS technology in the last twenty years.

    6     (find) out what is going on under the ground, scientists need to study earthquakes. Every earthquake, either small     7     big, can teach scientists something about how much the ground will shake in the future. Unluckily, no one can predict (预测) when an earthquake will hit. Scientists just have to prepare to study all earthquakes    8     hit.

But silent earthquakes like the one in Sumatra change the game for scientists. These silent earthquakes happen all over    9     world. Sometimes, a silent earthquake happens just before a regular one, both of which might be related. By studying silent earthquakes, scientists hope to better understand regular earthquakes and    10    (possible) predict them.

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.