There is little doubt that Earth is getting warmer and warmer. In 2013, many people     1    (shock) by a news photo of a dead polar bear which appeared to have starved to death. Experts claimed that low sea-ice levels       2    (cause) by climate change meant that the bear could not hunt seals as before, so it had to travel greater distances     3    (find) food. Then what is causing the increase in the global average surface temperature? Climate scientists often mention a key climate process called the “greenhouse effect”,     4    has two common meanings: the “natural” greenhouse effect and the “man-made” greenhouse effect. The “man-made” greenhouse effect has now become     5    big problem. There is strong and comprehensive evidence     6    the rise in temperature has led to an increase in extreme weather and natural disasters worldwide. Actually, news reports are     7    (frequent) broadcast about extreme rainstorms and heatwaves     8    (cause) deaths and economic losses. Continued greenhouse gas emissions will result in further warming and long-lasting changes to the global climate. This requires the attention of people all over the world. We as individuals can also reduce our “carbon footprint” by     9    (restrict) the amount of carbon dioxide our lifestyles produce. It is our responsibility     10    (seize) every opportunity to educate everyone about global warming.

Without the usual smoggy days, local     1    (resident) have been happy with the air quality since the heating season started. They open the window to air their homes. In social media, pictures of blue skies and white clouds     2    (frequent) appear,     3    (show) people's excitement with the clear days.

In Shanxi,     4     major coal production province, burning coarse coal(粗煤)for heating used to be a main source of air     5     (pollute). The government has been striving to change all this. It has launched a campaign to replace coarse coal     6     clean fuels for heating since 2017.

More than 38 percent of the heating companies- in Shanxi had applied advanced equipment with higher efficiency and     7    (low) emissions (排放)by the end of 2019,     8     (compare) with 25.5 percent at the end of20l7. It     9     (estimate) that the number can reach 50 percent by the end of this year,     10     is the goal of the government.

A new study led by researchers at the Yale School of Public Health and published in the journal Lancet Planetary Health, finds that China’s countrywide ban     1     traffic mobility from February 10 to March 14 greatly limited automobile emissions and sharply reduced the     2     (country) often severe air pollution.

The improved air quality, in turn, prevented thousands of pollution-related     3     (death), an     4     (estimate)12,125, more than lives lost from the epidemic(流行 病), the study finds.

“This is a very surprising result. The epidemic continues to be a terrible thing for China and the rest of the world, but the decrease in emissions that accompanied     5     has actually presented some positive health results,” said Kai Chen, assistant professor at the Yale School of Public Health and the study’s first author. “The question is, how can we have one without the       6     ?”

Although the findings cannot be directly applied to other countries due   to   different severity of and responses to COVID-19, as well as     7     (differ) air pollution levels and population characteristics, reduced air pollution levels     8     (detect) in other Asian and European countries and the U.S.    9     their own lockdowns (封城), Chen said. He notes that this reduction in pollution has     10     (like) brought about similar health benefits.

At 8,844.43 meters high, Mount Qomolangma is     1     (tall) mountain on Earth. While     2     is famous for its challenging hike, parts of the mountain are facing a problem: garbage. Every year, thousands of     3     (visit) throw away tons of trash, including soda cans (罐) and plastic bags.

According to the UN, over 140 tons of trash have been left on the mountain. To reduce trash, China is limiting the number of people     4     can climb the mountain’s north side. Only 300 people will     5     (allow) to climb it each year, and only during spring.

Local residents cleaned the mountain last year,     6     (remove) trash at a height of 5,200 meters. They     7     (collect) about 8.4 metric tons of trash, according to figures from the Tibet autonomous region’s government (西藏自治区人民政府).

This year, the local government plans to spend 4 million yuan       8    a new clean-up campaign, setting up stations to sort, recycle and break down garbage collected from the mountain.

In addition to trash, workers will also collect the bodies of     9     (die)   climbers. As of the 2019 climbing season, more than 300 people have died on Qomolangma, with 12 deaths this year.

A group of artists will try to turn some trash into artwork. They will show these works     10     (local), to remind people not to leave trash when climbing the mountain.

With the     1    (develop) of industry, air pollution is getting more and more serious. In Beijing, many people suffer different kinds of illnesses because     2     air pollution.

Air pollution is caused by the following     3    (reason): about half of the problem is caused by vehicles. There are more and more cars, buses on the roads, and they give off     4    (poison) gases. 25% of air pollution is caused by factories. Another factor is the smokers. Smoking not only does harm to their health     5     to others.     6    (beside) these, about 10% of air pollution is caused by other reasons.

We should take some measures to fight     7     pollution. New fuel can be used to take     8     place of gas. We can plant more trees. If everybody realizes the     9    (important) of the environment and does something to stop pollution, the problem will     10    (solve)．