1 . In the name of social distancing, this year’s graduation ceremonies have become different. However, one tradition has continued to exist — the square graduation cap, commonly known as a mortarboard hat.

European scholars (学者) have been wearing caps since the first universities were started in the 11th century, but their early caps looked more like Amelia Earhart’s pilot cap than the square caps we know today. Early scholars first used the pileus (伞状帽). By the 14th century, pileus caps were becoming taller, similar to a modern chef’s hat but shorter. This style, the “pileus rotundus”, was used mainly by university students studying law, medicine, and science.

By the middle of the 16th century, a new cap style made waves in universities: the “pileus quadratus“, a soft, square cap that required less material to make. Soon the two styles, round and square, became symbols of different statuses. One century later at the University of Oxford, under-graduates wore the older, rounded caps, while those with higher degrees were allowed to wear the pileus quadratus.

The first American colleges were started in the mid-1600s, and their class structures and degree requirements followed famous English universities. And European scholarly traditions were kept- including ideas of proper academic dress. Today, American graduates in law, medicine, and philosophy still wear rounded caps, but undergraduates always use the square cap.

Although the square hat has a centuries-old history, new cap traditions are popping up across the US. About 100 years ago, students began moving their tassels (流 苏) from the right side of their cap to the left. To this day there are no formal rules on where the tassel should be placed, but the act of moving it from one side to the other has been widely popular.

While the ways in which we observe graduation may change, the four-cornered black hat will likely remain a sort of culture for academic achievements —a symbol of celebration with roots going back to medieval Europe.

2 . Imagine this: You’re digging a well, and instead of hitting water, you unearth a headless human body made of pottery. This actually happened to farmers in Shanxi province in central China in 1974. Local archaeologists heard of the find and biked over to investigate. They realized that the figure had come from a tomb built over 2,000 years ago for China’s first emperor, Qin Shihuang. Archaeologists finally discovered three separate pits (穴) filled with 8,000 life-sized statues, all made from terracotta — a type of fired clay.

About a mile away from these pits, there’s a large mound (山丘). Archaeologists know that this is the main part of Qin Shihuang’s tomb, but they have never looked inside. They have left it alone out of respect for the first emperor and to protect the tomb as it is.

“Many people wish to see the treasures and mysteries inside, but we cannot,” says Xiuzhen Li, an archaeologist. Opening the tomb could damage its contents. Someday, Li hopes, we’ll have technology that will let us see inside the main part of the tomb without opening and disturbing it.

“Probably in the near future we’ll have some new technology that can see inside like an x-ray,” she says. Scientists are working on techniques that make it possible to see underground. Another idea is that a tiny robot could enter through a small hole and capture videos of what it sees. Even if this robotic exploration is done very carefully, however, it would still damage the tomb. For now, the Chinese government prefers to wait to do anything until they have even better technology.

In the 17^th century, people believed more in the church than in facts, and people like Galileo Galilei,    1    proved the idea that “the Earth is not the center of the universe”, were often punished by the church with no one    2    (come) to their defence. The church and many people tended to ignore the facts and didn’t want to challenge    3    they had always comfortably believed. It is not surprising that people wanted to believe these primitive ideas as they had been put forward    4    the great philosopher Aristotle.

About the same time as modern humans pushed into Europe, some of the same group that had paused in the Middle East spread east into Central Asia, where they       1     (eventual) reached as far as Siberia, the Korean peninsula(半岛), and Japan. Here begins one of the last chapters in the human story—the peopling of the Americas.

Most scientists believe that today’s Native Americans descend(是……的后裔)from ancient Asians       2     crossed from Siberia to Alaska in the last ice age, when low sea levels would have exposed a land bridge       3     the continents. They probably traveled along the coast—perhaps a few hundred people moving from one piece of land to the next, between a       4     (freeze) ocean and a wall of ice. “A       5     (coast) route would have been the easiest way in,” says Wells. “But it still would have been a hell of a trip.” Once across, they       6     (follow) the immense herds of animals into the mainland and spread to the tip of South America in as little as a thousand years.

Genetic researchers can only tell us the basic outlines of a story of human migration that is richer and more complex than any ever       7     (write). Most of the details of the movements of our ancestors and their countless individual lives in different times and places can only       8     (imagine).       9     thanks to genetic researchers, themselves descendants of mtDNA Eve and Y-chromosome Adam, we have begun to       10     (lock) important secrets about the origins and movements of our ancient ancestors.

Acrobatics, whose Chinese name is zaji, is popular with people. Modern acrobatics mainly depends on performer’s soft body    1    (complete) a series of highly difficult movements. It can     2    (find) in many of performing arts and many sports. Acrobatics is often associated with the activities     3     make extensive use of gymnastic skills, such as circus and gymnastics, but many other athletic activities, such as wushu, ballet and diving may also employ     4    (element) of acrobatics. The items in Chinese acrobatics include lion dance, oral stunts, pagoda of bowls, juggling, wire walking, etc.

Chinese zaji can date back to Neolithic times. As one of the traditional art forms, acrobatics has been popular among the Chinese people for more than 2, 000 years. As early as the Warring States, there appeared early stages of acrobatics. By    5     time of Han Dynasty, the acrobatics art further developed both in content and form and there appeared superb performances     6     music accompaniment on the stage. In the Tang Dynasty, the most flourishing period in ancient China, the number of acrobats increased     7    (significant) and their performing skills gained much improvement.

There is much    8    (stable) involved in dangerous movements and quietness in actions. The modern acrobatics aims at creating graceful stage images,     9    (harmony) musical accompaniment, and good supporting effects, props and lighting. In the past 50 years, many Chinese acrobatic troupes (表演团)     10    (visit) more than one hundred countries and regions around the world, winning dozens of prizes in the international acrobatic festivals and championships.

During China’s dynastic period, emperors planned the city of Beijing     1     arranged the residential areas according to social classes. The term “hutong”,     2     (original)meaning “water well” in Mongolian, appeared first during the Yuan Dynasty.

In the Ming Dynasty, the center was the Forbidden City,     3     (surround)in concentric(同心的)circles by the Inner City and Outer City. Citizens of higher social classes     4     (permit)to live closer to the center of the circles. The large siheyuan of these high-ranking officials and wealthy businessmen often     5     (feature)beautifully carved and painted roof beams and pillars(柱子). The hutongs they formed were orderly, lined by     6     (space)homes and walled gardens. Farther from the center lived the commoners and laborers. Their siheyuan were far smaller in scale and     7     (simple)in design and decoration, and the hutongs were narrower.

Hutongs represent an important cultural element of the city of Beijing. Thanks to Beijing’s long history     8     capital of China, almost every hutong has its stories, and some are even associated with historic     9     (event). In contrast to the court life and upper-class culture represented by the Forbidden City, the Summer Palace, and the Temple of Heaven, the hutongs reflect     10     culture of grassroots Beijingers.