When Halloween arrives, you know there is bound to be some mischief (恶作剧). So I wasn’t     1     (entire) surprised when I opened my front door that night to see my candy bowl completely—and very suddenly—empty. To be fair, this was after some light rain    2     (clear) the street of most trick-or-treaters and the youngest had already made the rounds. I never saw    3     took it, but I did shout “Happy Halloween!” into the night air.

Soil     1     (find) nearly everywhere. And it seems unlikely that we would ever lose all the soil on Earth. However,     2     we may lose is the deep and rich agricultural soil because of over-farming, a lack of plant cover off-season and a collection of salt from watering and fertilization (施肥).     3     proper measures, some experts warn, there could be serious agricultural soil problems before the end of this century.

Davyon Johnson, an 11-year-old boy, was honored by his community after saving two lives in one day. On Dec. 9, a choking student tripped into the classroom     1     Davyon was. Davyon did the Heimlich immediately and saved him. Hours later, on his way home, Davyon spotted a house on fire. Everybody     2     (run) out except for an elderly lady. As the woman struggled     3     (move) using her walker, Davyon raced up the steps and helped her escape the burning building.

When a severe car crash occurs on a deserted road, the injured may not rely on nearby witnesses to call the emergency services. Now many modern smartphones     1     (equip) with crash-detection technology that uses data to determine when a car crash has occurred. An alarm     2     (play) by the smartphones will be sent to the services automatically. In an emergency situation the device detects     3     the crash takes place to share the location with first responders so that there’s a higher chance of survival for the crash victims.

The Port of Shanghai has been the busiest in the world for 14 years running after     1     (overtake) the Port of Singapore in 2010. The seaport, situated at the mouth of the Yangtze river,     2     (grow) to cover an area of 1.5 square miles since it was opened in 1842. From here, 500 million tonnes of goods is handled in a year. There’s enough space at Shanghai to receive this huge shipment, most of     3     consists of coal, steel and machinery.

Before some of the greatest explorers in history were born, Vikings had already navigated (航海) their way around the world. But with no     1     (compass), satellites or radios, how did they manage     2     (map) the globe so impressively? The answer is     3     (simple) than you might expect — experience. Viking travelers studied the positions of the stars and the sun. Even the colour of the sea and movement of the waves would give them an     4     (indicate) of how close they were to land.

The Terracotta Army (兵马俑) was found in 1974 near Xi’an. It is formed of more than 8,000 sculptures, which     1     (bury) alongside the emperor Qin Shi Huang more than 2,200 years ago. Now, researchers have recreated the shoes of one soldier and analysis of them     2     (suggest) that shoes worn by the terracotta sculptures were surprisingly flexible and slip resistant. If the recreated shoes     3     (true) reflect the real ones, they can help build a better picture of     4     Qin dynasty soldiers wore and how this might have aided them in battles.

Harbin,    1     (know) for its ice and snow festivals, became very popular last winter. An increasing number of tourists rushed to the “Ice City of China” to experience the best of ice and snow culture. Besides the frosty delights, the city still has much more     2     (offer) all year around, including its traditional European-style architecture, unique cuisine and cultural events. The city’s individual attractions make     3     a must-see spot no matter the weather.

Zhao Chuang is a science artist working in Beijing,    1     job bridges science and art by painting and sculpturing ancient extinct species. Zhao reproduces each element described in papers on the history of life in an artistic way, and the     2     (blank) in scientific research are filled by his logic and imagination. His painting of a prehistoric flying animal became the cover of important scientific journal Nature in 2006, a highlight in his career     3     a science artist.

Humankind’s growing need for food is running up against thousands of other species’ need for space. By 2050, humans may need to clear an additional 3.35 million square     1     (kilometer) of land for agriculture.     2     (transform) these largely natural habitats would squeeze more than 17,000 vertebrate species from some of their lands. But changing how and where food     3     (grow) can minimize the impacts. “We can feed the planet without messing it up too badly,” says conservation scientist David Williams.