Chinese traders were recorded as making voyages to the north coast of Australia from the 1750s, but were probably visiting Australia long before. Chinese men arrived in Australia in small numbers after the 1788 British settlement as free settlers and criminals. A small population grew rapidly after 1848 under a system of indentured (契约的) labor, after China had     1     its ports to foreign trade in 1842. They worked in rural New South Wales as cooks, farm laborers and etc.

Indentured Chinese     2     worked in all colonies variously as station hands, plantation workers, miners, on public works, cabinet makers, personal servants and in laundries. Most came from the south-eastern provinces of Guangdong and Fujian.

Due to labor     3     in West Australia, the Colonial Government organized Chinese contract labor between 1847 and 1898, most working as laborers, cooks and gardeners. Many Chinese people came from rural backgrounds and brought with them     4     and water management skills. By 1885, there were 54 Chinese market gardens in Sydney. By 1901, 67% of New South Wales market gardeners were Chinese.

Gold rushes in Victoria in the 1850s and New South Wales in the 1860s significantly     5     the population of Chinese immigrants in Australia; about 45,000 prospectors arrived in Victoria alone in 1854-58. Numbers continued to increase as gold and other     6     were discovered in Queensland, Northern Territory and Tasmania.

When mining became less     7    , many Chinese people worked successfully to provide goods and services such as furniture making, market gardening, fishing and, particularly, store-keeping including the import and export of goods from overseas. Chinese goods, especially tea, silk, vegetables, herbs and other spices were highly sought-after items of trade by non-Chinese people. Tea rooms, importing and selling many varieties of tea, were very popular. Chinese silk was turned into     8     evening wear and cloaks by Chinese tailors and seamstresses.

Today there is a culturally diverse Chinese     9     in Australia with links to south-eastern China as well as Vietnam and Hong Kong. The Chinese communities in Australia are brought together every year by     10     of Lunar New Year.

For centuries, two of the most intriguing question about Leonardo da Vinci’s “Mona Lisa” were “Who?” and “When?” A discovery made at Heidelberg University in 2005 pretty much answered both. A note written in a manuscript in the library confirmed the     1     of da Vinci’s first biographer, Giorgio Vasari: that the sitter was a merchant’s wife, Lisa Gherardini. The note also helped     2     the masterpiece to between 1503 and 1506.

A third mystery—“Where?”—is still in dispute, But on June 3rd a French engineer, Pascal Cotte, declared that he and a collaborator had identified the landscape in the background of the painting. Arguments had once been made for     3     of countryside in the Marche region and between Milan and Genoa. During a presentation in Vinci, near Florence, Mr. Cotte argued that the artist was more     4     depicting a part of his native Tuscany-one that much interested him at the time. According to this theory, da Vinci     5     the area not as it was, but as, in an unrealized scheme, he intended it to be.

Mr. Cotte, who was asked by the Louvre (where the “Mona Lisa” hangs) to create a digital image of the painting, is the inventor of the multispectral (多光谱的) camera: a device that can detect not only the drawing below the surface of an oil painting, but also, where they exist, intermediate layers of work. It was among these, under what appears to be a     6     rock, that he found a preparatory sketch showing that da Vinci intended it to represent a castellated(城堡形的) tower.

The landscape of the “Mona Lisa” also includes a huge steep cliff. That is similar to one that da Vinci included in a sketch of a fortress(堡垒)     7     by Pisa and Florence in the war that broke out between them in 1503 (around the time he was painting Gherardini). The fortress with the nearby cliff—and a tower, known as the Caprona tower—all overlook the river Arno as it snakes from Florence to Pisa. All three also     8     in drawings made by da Vinci to illustrate a plan about which, says Mr. Cotte, he became “obsessive”.

Mr. Cotte argues that a channel that     9     through desolate countryside at the right of the “Mona Lisa” is too wide to be a road, as some have speculated, and is instead the dried-up bed of the Armo as da Vinci pictured it once his plan had been adopted.

It never was. But if Mr. Cotte’s theory is right, it might just explain why Gherardini, a Florentine, wears such a     10    , if mysterious, smile.

Ukraine, a nation whose history has experienced long periods of occupation from other countries, today wrestles(摔跤，全力应付)between war and peace, as well as between corruption and reform. The nation     1    the Black and Azov seas to the south and lies next to several Eastern European nations, including Russia.

Ukraine declared independence from the former Soviet Union in 1991. Its president is directly elected by voters. The prime minister is the head of the central government, which is separated along     2    , legislative and judicial branches.

The country’s post-Soviet political life has been controversial, disturbed by persistent charges of government corruption and fraud. Large-scale protests at the end of 2013 turned violent in 2014, leading to the ouster(罢免)of the government and     3    in the heavily ethnic Russian eastern regions of Ukraine. Russia annexed(抢占)the Crimea region of Ukraine in early 2014, a     4    by Moscow that has been widely criticized by the international community.

Ukraine joined into a free trade area at the beginning of 2016, and the World Bank noted that the country’s economy did begin to show signs of a weak recovery. A broader recovery has been held back, the World Bank says, by continuing conflict in the east and the need for reforms.

Ukraine entered a long-awaited agreement with the European Union in September 2017, a move that brings the country a step closer to the goal of joining the European Union and NATO.

Services, industry and agriculture are Ukraine’s three largest economic sectors. The nation     5    relies on natural gas imports from Russia to meet its energy needs. Agricultural production and energy consumption can be made more     6    , and in doing so Ukraine could play an important role in global food security, according to the World Bank. Culturally, Ukraine is influenced by Western and Central Europe, Russia to the east and by religion— the predominant faith in the country is Eastern Orthodoxy. The country has a rich history in literature, music, architecture and folk art, including “pysanky”, Ukrainian Easter eggs. Ethnic Ukrainians form the overwhelming majority of the country’s population, with ethnic Russians serving as the largest     7    group.

Ukraine is a member of major international and regional organizations, including the United Nations, the World Trade Organization, the European Bank for Reconstruction and Development and the Commonwealth of Independent States.

The Beijing Winter Olympics and Paralympics saw many excellent athletes compete on the ice and snow,     1     an enthusiasm for winter sports in China. In fact, the country has had a deep relationship with winter sports since ancient times, with skiing     2     in the Altay prefecture(县) of Xinjiang Uygur autonomous region.

In 2005, cave paintings of Altay people hunting on skis with poles were discovered, which archaeologists estimated could be more than 10,000 years old. Since then, Altay has been     3     by many as one of the birthplaces of skiing, according to Xinhua.

As one of the richest collections of ancient rock art in China, there are herds of camels, sheep, wolves and human     4    . The painting on the roof of a cave in Dundebulake village of Altay prefecture depicts humans on skis, bending their knees as they travel alongside animals, including deer and moose.

The rock art in Dundebulake is well     5     because the pictographs are well hidden in the cave. Additionally, Altay’s dry climate has been a useful preserving     6    , according to a 2016 research paper published by the Hebei Normal University. Unique geographical and climatic     7     make skiing an indispensable part of local people’s lives. The climate in Altay is mild and not too windy, so skiers are less     8     by weather conditions, allowing them to safely move faster.

Unlike the modern skis we use nowadays, fur skis have been used as a means of transportation for the snowfield     9     of Altay for more than 100 centuries, according to rock carvings uncovered in the area.

Making skis has been a traditional skill. The handmade skis have a layer of horse skin. The fur on the horse skin can help decrease friction when they     10     down the hill, while the skis also prevent skiers from falling when they walk up. At the same time, they have a wooden stick in hand to keep balance, according to China Daily. Fur ski competitions have been held annually by the local government. Many locals would display their maneuvers at the competitions.