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.

Peru     1     (lie) on the Pacific coast of South America with three main     2     (area): the land running along the coast, the Andes Mountains, and the Amazon rainforest. In the 1400s and 1500s, Peru was the centre of the     3     (power) ancient Inca Empire, whose emperor lived in the site Machu Picchu. In the 16th century, Spain took control     4     Peru. In Amazon Rainforest, you take     5     boat to reach your accommodation. Three days will witness the unique plants and animals there.     6     (walk) on the path through the Andes Mountains leads to Machu Picchu. You’ll     7     (amaze) by this destination.     8     (especial) amazing is the Incas’ dry stone method of building. Stones are cut in exact sizes     9     (hold) walls together other than the perfect fit. In Cusco, you must admire architecture. In Lake Titicaca, both the island     10     the local homes are made of water plants from the lake.

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).

Peru is a country on the Pacific coast of South America,     1    includes three main areas: narrow, dry, flat land     2    (run) along the coast, the Andes Mountains, and the Amazon rainforest. In the high plain area is Lake Titicaca, the highest lake in the world, on which boats can travel. Peru has abundant plants from desert grasses     3    vast areas of jungle.

Peru     4    (rule ) by Spain from the 16th century to 1821. So Spanish is     5    (official) spoken in Peru. The ancient Inca capital, Cusco, is a popular destination for the     6    (tour) as it is close to the famous Inca ruins of the city of Machu Picchu.

There are two especially interesting things for us     7    (admire) about the Inca civilization. The first is the roads and paths they built to connect     8    (they) important cities. Second, the Inca built wonderful cities,     9     there were no markets in these cities. One of the interesting     10    (question) of history is how the Inca lived without shopping.

The Singing Sands Mountain(鸣沙山)is located in Dunhuang in    1     (west)China. Whether you walk through the quicksand    2    slide down a sand mountain, you can hear loud noises from beneath your feet. That’s    3    it is named“The Singing Sands Mountain”. There is a spring lying between the tall sand mountains. This spring, which looks like a crescent moon(月牙),    4    (exist) for thousands of years and has never dried up. The formation and continuous existence of the Crescent Spring are greatly related to its topography (地势).

The flowing water gathers here along the landform and overflows through a porous(可渗透的) geological layer    5    (form) the Crescent Spring. Although its     6    (extreme) dry here, with the annual evaporation being more than 60 times that of the annual precipitation, the stable water source ensures a sustainable water supply to the spring.It’s also due     7    the low-lying terrain(低洼).Whenever there’s a sandstorm, it forms an upward spiral air flow between the surrounding sand mountains, sending the sand at the foot back to    8    top of the sand mountain,and saving the Crescent Spring from    9    (wallow)by quicksand.

The ancient Silk Road once passed by the Crescent Spring. And today, it has become a romantic paradise for    10     (visit).