The day starts early for Zheng Baogang and his tree-planting team. At about 5 a. m., they are on their way to the site of     1     abandoned mine in Huzhou, Zhejiang province.

Since June, they     2    (work) to restore the land to its past natural glory. It is the most difficult reforestation project related to the former coal mines and stone quarries in the area     3     Zheng has participated in. The Huzhou mine was put into operation in the late 1980s     4     it is about 200 metres deep now. Today, the entire site for restoration is more than 200,000 square metres.

    5    (wear) ropes and straps like mountaineers, Zheng and his team take     6    (step) down the cliff to loosen the soil and plant trees or grass seeds every day. In summer, the ground temperature can reach over 40°C, while in winter, it is     7    (extreme) cold.

Although the work is     8    (danger) and laborious, Zheng says it is rewarding to see the brown fields turning green. Estimated to be completed by the end of this month, the project will enter a two-year maintenance period     9    (restore) the area’s greenery.

In the past decade, Zheng has helped     10     such work at over 60 former sites. Some sites are even reviving parklands.

Today, much of the world’s ocean is still a mystery. Only 5 percent of it     1     (explore) so far. In fact, we know more about some areas of Mars     2     some parts of the world’s ocean.

New technology, however, is helping scientists explore these     3     (hide) worlds. For example, scientists are using     4     underwater vehicle called DeepSea to explore seamounts-underwater mountains.

Scientists have used DeepSea to study Las Gemelas, an area of seamounts near Costa Rica. A huge     5     (vary) of species live around Las Gemelas. Some of these species may have chemicals     6     can help people fight illnesses.

The     7     (deep) location of the earth is the Mariana Trench in the Pacific Ocean. The ocean floor there is     8     (approximate) 11,000 meters deep. In 2012, filmmaker and explorer James Cameron reached the Mariana Trench in a vehicle called DeepSea Challenger. He was the first     9     (complete) the journey alone. Cameron took photos and made videos on the ocean floor. Deep sea exploration also helps us     10     other ways. For example, we are learning how underwater earthquakes cause tsunamis. As Cameron says, “This is the beginning of opening up a new frontier.”

Earth Day was founded in 1970 as a day of education about environmental problems, and Earth Day 2020     1     (fall) on Wednesday, April 22 — the holiday’s 50th anniversary. The holiday is now a global celebration that’s sometimes extended into Earth Week, a full seven days of events focused on green living.

    2    (elect) to the U. S. Senate (参议院) in 1962, Senator Gaylord Nelson was determined to convince the federal government that the planet was     3     risk. In 1969, Nelson developed the idea for Earth Day after     4     (inspire) by some teaching activities     5     were taking place on college campuses around the United States.

Denis Hayes, a young activist who had served as student president at Stanford University,     6    (select) as Earth Day’s national coordinator (协调者), and he worked with     7     army of student volunteers and several staff members from Nelson’s Senate office     8    (organize) the project.

The first Earth Day was effective at raising     9     (aware) about environmental problems and transforming public attitudes. Earth Day kicked off the “Environmental decade with a bang,” as Senator Nelson later put it. The theme of Earth Day 2020 is “climate action.” EarthDay.org hopes it will be the     10     (large) volunteer event in history.

In recent years, climate change has had a great impact     1    animals. In 2013, the whole world     2    (shock) by a news photo of a dead polar bear on Norway’s Arctic island of Svalbard. Due to the rise in temperature, the polar bear seemed     3    (die) from lack of food.

According to climate scientists, a key climate process,     4    is called the “greenhouse effect”, includes the “natural” greenhouse effect and the “man-made” green-house effect. The former refers to the fact that heat from the sun     5    (enter) the atmosphere and warms Earth’s surface.

Greenhouse gases in the atmosphere trap some of the heat,     6    (keep) Earth’s climate warm and habitable. However, the latter has become    7    big problem. When people burn fossil fuels, more heat energy is trapped in the atmosphere and causes Earth’s surface temperature to rise    8    (quick).

The evidence shows that the rise in temperature has led to an increase in extreme weather and natural     9    (disaster) worldwide. Climate scientists have warned that this warming trend will become     10    (bad) if we do not take appropriate measures. The severe situation requires people allover the world to pay more attention to it.

Located in the northwest of Hunan Province, about 300 kilometers away from Changsha, the capital of Hunan, Zhangjiajie,    1     covers a total area of 9,653 square kilometers, is a tourist city for its unique natural scenery and abundant tourism resources. Zhangjiajie     2     (gıve) the title of “World Geological Park” in 2004.    3     (actual), Zhangjiajie, honored as “the most fantastic mountain under heaven” and “a walking Chinese landscape (盆景) painting”, is also widely praised as “    4     enlarged potted landscape” “a mini fairyland” and “a maze (迷宫) of nature”, attracting a growing number of tourists     5     home and abroad.

Since it was discovered in the 1980s, the tourism industry     6     (become) the leading industry in Zhangjiajie, which has stimulated the     7     (develop) of other industries related to tourism. At the same time, eco-tourism has been developed rapidly in Zhangjiajie. When you come to Zhangjiajie, you can fully appreciate     8     (it) magnificent (壮丽的) natural scenery and experience appealing folk custom as well as other thrilling tourist     9    (activity), and you will be deeply impressed by     10     is performed by the minorities there.

lt must be an exciting, joyful and unforgettable tour of Zhangjiajie.

The oldest and most common source of renewable energy     1    (know) to man, biomass (有机燃料) is one of the most important forms of energy production in the United States and elsewhere. Since such     2     wide variety of biomass materials is everywhere — from trees and grasses to agricultural and city-life wastes — biomass     3    (promise) to play a continuing role in providing power and heat for millions of people around the world.

According to the Union of Concerned Scientists（UCS), biomass is a kind of renewable energy source     4     produces no carbon dioxide (二氧化碳), because the energy it contains comes from the sun. When plant matter     5    （burn), it gives off the sun’s energy. In this way, biomass serves     6     a sort of natural battery (电池)for storing the sun’s energy. As long as biomass is produced     7    (continue) — with only as much grown as is used — the “battery” lasts forever.

According to the Energy Information Administration, biomass     8    (be) one of the leading renewable energy sources in the United States for several years running through 2007,     9    (make) up between 0.5and 0.9 percent of the nation’s total electricity supply. In 2008 — although the numbers aren’t all in yet — wind power probably took over first place because of the rapid     10    (develop) of wind farms across the country.

Dragons, a famous     1     (imagine) beast born from fantasy, are often present in stories in the west and east. In both cultures, dragons are     2     (general) recognized as massive creatures capable of flying. They have great power with magical abilities. However, due     3     their different cultural roots and images, there exist significant differences in the way dragons     4     (regard) in the west and east, particularly in China.

In traditional Chinese culture, a dragon is a symbol of luck, power and high ‘status. They can cause weather changes and bring rainfall to the fields     5     (ensure) rich harvests. They are considered divine (神圣的) creatures,     6     hold an important position as the head of the four spirits. Therefore, to symbolize their power, ancient Chinese     7     (emperor) decorated their clothes with dragon patterns. These clothes are known as dragon robes. Many Chinese view the dragon as a national symbol, proudly     8     (refer) to themselves as “descendants of the dragon”. In the west, however, a dragon symbolizes     9     evil creature that spreads violence and terror throughout the land. They are believed to be transformed by the devil, with the ability to breathe fire or spit poison.

Today, dragons continue to evolve, exceeding traditional boundaries and finding new significance in global culture. No longer     10     (associate) with evil or good, they are more as complex characters with their own unique personalities and motivations.

In a new cartoon named Turtle Journey, Greenpeace UK, an environmental organization,     1    (highlight) ocean destruction from the perspective of a family of sea turtles.

    2     (create) the film, Greenpeace UK teamed up with Aardman Animations, as well as Oscar-winning actors and stars. The    3     (power) film follows the family of turtles as they make their way across the seafloor to their home on a coral reef. “Our ocean     4    (drive) to breaking point during the past few years but it’s a story that doesn’t get told often enough,” says Will Mccallum, head of ocean at Greenpeace UK. Ocean damage is     5     (serious) affecting sea turtles and other sea creatures, many of which    6    (face ) with extinction at present.

“The story of this turtle family     7     (attempt) to get home in the damaged and changing ocean is a     8     (real) for many ocean creatures that are having their habitats destroyed due to human activity,” says actress Olivia Colman,    9    voices a character in the film. “It is my hope     10     this film can inspire more people to take action to protect our ocean.”