1 . When you swim on the beach and sea, have you ever accidentally drunk the seawater? How did it feel? It must have tasted salty. So, why is the seawater salty?

Seawater is water that comes from the ocean. Seawater can be salty because it contains an average salt content of 3.5%. This is also a place for the salt farmers to produce cooking salt and other salt.

Some theories explain that seawater comes from rainwater that falls and flows through rivers and estuaries (河口) where the seawater will be fully filled and again formed clouds because the steam uses the help of the sun. When we talk about this, we talk about the rainwater cycle. But when the rainwater cycle occurs, the water that passes through the river carries mineral salts. These mineral salts are obtained from various places of the land starting from rocks and soils that the rainwater flows through, these remaining mineral salts make seawater salty, so the salinity of seawater is different in each part of the world. But it is certain that seawater is salty or has high salinity.

The saltiest sea in the world is the Red Sea. There the temperature is extremely hot so that evaporation (蒸发) is greatly carried out. High evaporation, coupled with little rainfall and little input of water from the river, causes its highest level of salinity. There is also the Dead Sea, which is nine times saltier. Due to the high salinity, when you swim there, you can float. However, the Dead Sea is not a sea at all which is a lake geographically.

3 . For thousands of years, Chinese writers have travelled all over the country to take down notes about the geographical conditions of each city. Among them, well-known Chinese geographer and writer Li Daoyuan, in the Northern Wei Dynasty (386-534), composed his book, Commentary on the Water Classics, after studying the original literary version, Water Classics. He later expanded the river records to 1, 252 from the original 137.

The book is now being studied again by Professor Li Xiaojie and his team from Fudan University. They have been using drawing software and 3D modelling to recreate the waterway situations on a map based on the book description. So far, they have completed research on four rivers.

“Ancient people knew really well how to apply the power of nature to technical considerations,”Li said, giving the example of Qianjin’e, one of the most famous ancient water conservation projects in Luoyang, Henan. In order to lead the river into the city for irrigation (灌溉) in ancient Luoyang, the officials built a canal branch by separating a northwest-southeast river. However, the canal water wasn't enough to support the citizens in dry seasons. To solve that, on the northern side of the canal branch, the officials built a reservoir (水库) and a channel to lead the water to the canal branch, where the waterways would converge and flow together to the city.

In Commentary on the Water Classics, a total of 2, 800 cities are recorded with details. Still, the process of recreation takes much effort. After doing a lot of text analysis and fieldwork, the team has gradually created the model with 3D modelling software based on repeated deductions (推论).

For Professor Li, the book is not only a record of the natural landscape over 1, 000 years ago, but also a detailed description of humanity and culture and a treasure for today’s reference.

There are certain things on the Earth that we must not lose. The great animal migration across the Serengeti Plains or the towering pyramids of Egypt are such examples. Every country is proud of     1     (it) cultural or natural heritage sites,     2     must be protected. We are lucky to have UNESCO to oversee such an important task. It sees heritage as our legacy from     3    past, what we live with today, and what we pass on to future generations as well as sources    4    irreplaceable inspiration.

The incredible splendour of heritage sites is a     5     (remind) of the power of nature and the genius of man. As a nature reserve, Jiuzhaigou Valley is home to snow-capped mountains, thick forests, impressive waterfalls and lakes. This dream-like scenery makes us realize that nature has    6     (true) created a masterpiece. Similarly, standing in the shadow of the Borobudur Temple, as the sun rises over this grand historic building, we    7     (impress) with the effort and determination of the people who     8    (build) it with only primitive tools.

It is in heritage sites like this     9     we cannot help but be humbled, come to understand our limitations as human beings, and know that our duty is to protect them for generations     10     (come).

It’s time to update your maps, because the Earth now has a total of five oceans. Though     1     (accept)by scientists for some time, the Southern Ocean wouldn’t be found on any National Geographic maps—until now.

Cartographers(地图绘制者)at the National Geographic     2     (official)recognized the fifth ocean on World Ocean Day, 8 June 2021. The “new” ocean borders the Pacific, Atlantic and Indian Oceans, which is why geographers     3    (argue)for some time as to whether it was in fact unique enough to be classed as a different ocean,     4     just cold regions of the three oceans.

“There is of course just one interconnected world ocean, but it has traditionally been divided into four regions: the Pacific, Atlantic, Arctic, and Indian oceans, said Alex Tait on Twitter, who is     5     geographer in the National Geographic Society.

“Scientists have known for many years that the icy     6     (water)around Antarctica form a distinct ecological region defined     7     ocean currents and temperatures. But the international community, through the International Hydrographic Organization(IHO), has not agreed on a name and extent of this     8    (five) ocean region.”

While many called this region the Southern Ocean, some scientists called     9     the Antarctic Ocean, others said Austral Ocean. Either way, it is distinct enough to be     10    (deserve) of its new status.

The classical gardens of Suzhou, Jiangsu province, date back to the 6th century     1     the city was founded     2     the capital of the Wu Kingdom. Today, more than 50 of these gardens are still in     3     (exist), nine of which are regarded as the finest embodiments (化身) of Chinese “Mountain and Water” gardens.

Built in the 11th century on the site of an     4     (early) destroyed garden, Canglang Pavilion has the longest history among all the existing classical gardens in Suzhou. Naturally     5     (lay) out and well designed, it is called one of the four best gardens in Suzhou. The garden looks simple but natural. Without complex     6     (decorate), it combines buildings with scenery so well     7     the whole garden appears to be naturally endowed (赋予). Since many of the     8     (origin) features of the garden have been preserved, the garden has a high historical and artistic value.

The classical gardens of Suzhou     9     (be) the most vivid specimens(样本)of culture from the East Yangtze Delta region in the 11th to 19th centuries. The underlying philosophy, literature, art, and craftsmanship     10     (show) in the architecture, gardening as well as the handcrafts perfectly reflect the monumental achievements of the social, cultural, scientific, and technological developments of this period.

Shennongjia is a household name in China because it’s the home of the legendary “wild man”. Its folk tale spans the generations.

Between 1976 and 1981, the Chinese Academy of Sciences organized three large scale     1       (science) investigations. They have collected hair, footprints and waste suspected of belonging     2     a “wild man”, but some experts argue that most were the result of bears, monkeys or even human beings. They failed     3     (uncover) the myth of “wild man”, but discovered the area’s rich biodiversity. Although several hundred people have claimed     4     (they) as eyewitnesses of some giant apelike creatures in Shennongjia, there is no tangible evidence to confirm the     5     (exist) of a “wild man”.

Nowadays, Shennongjia’s attraction is not merely about “wild man”. Its appeal     6     (be) more about its lively ecology, rich biodiversity and karst landforms. Shennongjia’s beauty varies over the year as nature     7     (take) its course. Tourists can enjoy flower blossoms in spring, be shaded from the summer heat, appreciate red leaves in autumn     8     go skiing in winter.

The “wild man” legend has been passed on for generations by word-of- mouth. In 2016, the legend of "wild man" in Shennongjia     9     (add) to Hubei province’s intangible cultural heritage list. Today, tourists can visit Wild Man Cave,     10     eyewitnesses claimed that they spotted the creatures, and see “wild man” sculptures.

I’m so happy to know that you are planning to visit my hometown, the Cool City· Liupanshui.

Yours,

Li Hua