3 . Today, methane(甲烷) is a central but under-appreciated part of the fight against climate change. Human activity releases far less methane than carbon dioxide, but methane packs a heavier punch. Over the course of 20 years, a ton of the gas will warm the atmosphere about 86 times more than a ton of carbon dioxide. Chief among the reasons for methane emissions(排放) are the gassy output of raising farm animals (cows release it most), rice production (certain environments involve micro-organisms that make it) and the fossil fuel industry(pipelines leak it) .

Carbon dioxide remains in the atmosphere for centuries, making it hard to reduce its concentrations. By contrast, methane has a half-life of roughly ten years. If new emissions can be cut to below the rate at which old emissions reduce, the concentration of methane remaining in the atmosphere will soon fall, slowing global warming.

A big step would be to stop millions of tons of methane from leaking out of fossil fuel industry each year. Natural gas operators will be able to sell more gas in exchange for an acceptable investment so as to monitor and repair leaks. The International Energy Agency estimates that 40% of methane emissions from fossil fuels can be cut at no cost for firms.

The harder task is to reduce emissions from agriculture, but even here farmers can draw on new ideas, including developing new forms of feed for farm animals, and changing how rice field is irrigated.

However, politicians and the public tend to ignore the effects of cutting methane emission. But dealing with the gas with the efforts of the ordinary people would have a large effect at a relatively low cost.

Xi'an,or Chang'an as it was called for many centuries,has been a built-up urban area for over 3,000 years,and once     1    （serve）as capital for 13 dynasties.It is home     2     many immovable cultural heritages,three of     3     are on the UNESCO 's world cultural heritage list.

These days,the city has made     4    （effect）exploration in building modernity while preserving historical legacy（遗产）.A recent piece of news     5    （announce）by Shaanxi's cultural relic authority caused nationwide attention,that a ruin of ancient capital dating back to Qin Dynasty was unearthed during the construction of the Xi 'an MetroLine5.In order to protect the ruin,the metro line may have to change     6    （it）route.

    7     （face）the heavy and important task of protecting cultural relics while promoting urban construction,Xi’an made active    8    （attempt）.Rails of the metro system are built 15 to 20 meters underground in order to protect the ancient tombs which are     9     （usual）buried in the layer within5meters from the surface level.Besides,the metro constructors have also painted the walls inside the stations with historical stories,presenting       10     visual feast for citizens.

6 . Nobody wants to snack on plastic bags or soda rings, but according to a recent study from the University of Neweastle, we could be consuming roughly a credit card's worth of plastic every week.

Microplastic, which are less than a quarter-inch size and come in various shapes, have polluted the natural world and infiltrated(渗入)our bodies. The first clue to microplastic exposure in humans came around 2013, when scientists discovered plastic particles in seafood prepared for consumption. But in 2019, when the University of Newcastle study was published, the scientific community understood that the problem was considerably broader. Microplastics shed off clothes and tires and have been found in beer, honey, table salt and other food items. We breathe in plastic staying in the air and drink plastic floating in our drinks. It's no stretch to conclude that our exposure is significant. What we don't know is what this means for us.

The amount of evidence collected on this subject is growing rapidly, according to Scott Coffin, a toxicologist(毒理学家). Studies done on mice and rats have found that plastic in their bodies can severely damage cells and cause stress.

Because microplastics are too small to clean up, the only solution is to stop plastic waste at the source. And doing so would take a thorough adjustment, given that plastics are deeply embedded in our economy and lifestyle. Stopping using them would fundamentally affect countless industries, including textiles(纺织业), transportation and manufacturing.

"I think we need to have more studies coming out that are directly related to human health before we see a lot more concern from the general public," Scott said. "It takes a lot to convince people that something that is really convenient for them to use is something they should sacrifice."

The question of microplastics and human health needs more attention—from the scientific community ,the general public, the government and funding groups. The issue isn't being ignored, but it's not being prioritized either.

Since mid-July, a large part of Henan province has seen many heavy rains, during     1     time the rainfall over a few days in Henan exceeds (超过) that of a typical year, according to local officials. It was the first time that we     2     (suffer) such heavy rains in several days. Last month, more than 9.3 million people in Henan     3     (report) to have been affected by floods, with over hundreds of people     4     (lose) their lives. The government said that by 29^th July, huge funds had been raised by     5     (count) organizations and individuals voluntarily. Lots of netizens released videos of support and     6     (encourage) to people affected by the heavy rains,     7     (inspire) them to be more active in responding to frequent extreme weather changes.

We are reminded how fragile we human beings are when faced     8     natural disasters. Despite being struck, we firmly believe that our government will pay     9     it takes to save her people. As     10     matter of fact, rainstorm has no sympathy, but people have love.

A male elephant that broke away from the wandering elephant pack     1    ( send) back to its forest home on Wednesday in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, local authorities said.

Yuxi City headquarters in charge of monitoring the pack's migration (迁徙) took the     2     (decide) early Wednesday morning     3     ( prevent) the lone animal from entering heavily populated areas. At 3 p. m.，the elephant was caught and returned to the nature reserve. The animal appeared     4     (health) and did not suffer from any injuries.

The pack of 15 wandering wild Asian elephants travelled about 500 kilometers north from their forest home. The male elephant separated from the pack on June 6, and moved around in the     5     (city) of Kunming, Anning and Yuxi, with an activity area of 140 square kilometers and a walking distance of 190 kilometers. It had relied mainly on     6     was provided by the locals. The     7    (remain) 14 elephants have been moving southward recently but are still far from the reserve.

Asian elephants are     8     A-level state protection in China, where they are     9     (most) found in Yunnan. Thanks to determined protection efforts in recent decades, the wild elephant population in     10     province has grown to about 300, from 193 in the 1980s.