4 . Many people say dolphins are very intelligent.They seem to be able to think, understand, and learn things quickly.But are they smart like humans or more than cats or dogs?Dolphins use their brains differently from people.But scientists say dolphin intelligence and human intelligence are similar in some ways.How?

Fact 1：Talk to me

Like humans, every dolphin has its own "name". The name is a special whistle.Each dolphin chooses a specific whistle for itself, usually by its first birthday.Actually, scientists think dolphins, like people,   "talk" to each other about a lot of things, such as their ages, their feelings, or finding food.And, like humans, dolphins use a system of sounds and body languages to communicate.But understanding their conversations is not easy for humans.No one speaks dolphin's language yet, but some scientists are trying to learn.

Fact 2：Let's play

Dolphins are also social animals.They live in groups, and they often join others from different groups to play games and have fun—just like people.In fact, playing together is something only intelligent animals do.

Fact 3：Fishermen's helper

Dolphins and humans are similar in another way：both make plans to get something they want.In the seas of southern Brazil, for example, dolphins use an interesting strategy（策略）to get food.When fish are near a boat, dolphins show signs to the fishermen to put their nets in the water.Using this method, the men can catch a lot of fish.What is the advantage for the dolphins in doing so?They get to eat some of the fish.

5 . Scientists are urging that deep sea metal mining should be stopped temporarily. They warn in a report that it can cause severe damaging effects on Pacific Ocean areas.

The recently-released report examined more than 250 published studies on deep-sea mining. The research was examined by the Deep Sea Mining Campaign — a collection of not-for profit organizations. The report centers on mining activities related to small metallic particles(金属颗粒)，called nodules, found on the seabed. The material can contain different metals. Increasing demand for these metals has led to a rise in deep-sea mining operations. The metals are commonly used in battery manufacturing and other technology products.

However, the scientists warn that mining for these nodules will cause irreversible(不可逆的) damage to an ocean already under pressure. The operations will affect areas across the South Pacific, including the nations of Kiribati, the Cook Islands, Nauru, Tonga and Papua New Guinea.

The report notes that a moratorium is the only responsible way to move forward until certain conditions surrounding deep-sea mining can be met. The scientists are calling for additional study to fully understand the environmental, social and economic risks.

Andrew Chin is the report's lead researcher. He says in a statement that nodule mining will likely result in the loss of sea life and cause damage to deep seabeds for thousands of years. He adds that the operations can put people at risk who depend on the ocean and its continued health.

A company planning to be one of the first to carry out mining operations in the area is Canada's DeepGreen, which aims to begin by 2024. It seeks to mine metallic nodules to be used in power systems for electric vehicles. DeepGreen Chief Executive Officer Gerard Barron defended the company's plans in reaction to the report. He said deep-sea mining offered the best alternative to surface mining, which has long history of pollution and destroying forests and wildlife.

Days after graduating from Stanford University in 2014, Gayatri Datar set off for Rwanda to pursue     1     unique goal. In Datar’s life plan, what she always wants to do is rid the world of dirt floors, which can make people sick.

“It is easy to find bugs all over the place,” she explains. “Besides, when babies don't have diapers (尿布), they poop and pee (大小便) on the floors, which are really hard    2     (clean).

And they don’t look good, so people hate them.” Yet more than one billion people live on dirt floors,     3    they can’t afford anything better.

Datar’s start-up, Earthenable, sells an earthen floor     4     (make) of locally sourced clay, pebbles, and sand, sealed with special eco-friendly vanish (清漆). It costs about $70 per home, far     5     (little) than concrete.

Earthenable struggled at first.     6     (get) raw materials to rural villages proved costly. Masons (泥瓦匠) had to     7     (train) to install the floors. Quality was unsteady. Datar says:

“Everything that could go wrong did go wrong.”

These days Earthenable is becoming better and better. More than 4, 400 earthen floors have been installed, Datar reports, and customers love them. Earthenable has raised money     8    foundations, the U.S. Agency for International Development, and a     9     (compete) that supports   green   entrepreneurs.   Best   of   all,   Datar   is   working     10     (close)   with   Rwandan government officials who say they really want to remove dirt floors, too.

7 . Bill Shaver took a fishing trip in Missouri. On the way back home, he had to ________ for a bathroom break at a rest stop, with his car________ and the driver’s side door open.

When Bill returned to his car, he found that he had a special________. A pup jumped into the car and was________ him when he returned. The female pup was obviously________，so Bill gave her the only thing he had left to eat and she finished it________.

Bill made sure the pup had no________ looking for her in the rest stop area. Then, he took a picture of her and sent it to his ________, Angela, letting her know that the pup was coming home with him. The couple had often taken care of________ animals, so Angela instantly agreed to________ the dog. After a few hours, Bill and his________ partner were back home. Angela gave her a good meal and________ her a bed on the floor in their room.

They named her “River”, because she met Bill near a river. The day after Bill brought her home, River started________ her new surroundings and soon________ to it. She was also taken to the veterinarian (兽医). There was nothing ________, and, after taking some________, it didn't take long before River became fully________.

River now loves her new life, and she certainly loves all the loving________ she receives. And her entire life was________ when she decided to catch a________ with a stranger.

8 . In October 2015, Shah began picking up rubbish from the beach every Sunday morning. At first, it was just him and a neighbor, and then he began _____ others to join in. Word spread and with help from social media, more volunteers got involved.

Shah hasn’t stopped since. He’s now spent 209 weekends _____ this mission inspiring more than 200,000 _____ to join him in what’s been called the world’s biggest beach cleanup. By October 2018, Versova Beach was _____ clean and Shah’s cleanups expanded to another _____ as well as a stretch of the Mithi River and other regions of India.

For Shah, the work has always been a personal journey, but it has earned _____ attention. After he was honored as a “Champion of the Earth” by the United Nations in 2016, Bollywood celebrities and politicians _____ his mission and joined in his cleanups.

Today, Shah is also working with coastal communities to _____ plastic pollution at one of the sources. In areas lacking waste management systems, _____ often end(s) up in streams and rivers that empty into the ______. Shah and his volunteers ______ and assist villagers in reducing, managing and recycling their plastic waste.

“This world ______ too much. I think you must talk less and do action more,” he said. “Every citizen on this planet must be in for a long pull. I feel the ______ to do something for my planet, so this will ______ for life. If each one could start, this journey could become ______. Can we do it together?”

9 . Global warming does more than just kill plant species — it also changes the way plants grow. Researchers at Martin Luther University Halle — Wittenberg(MLU) joined forces with the Leibniz Institute for Plant Biochemistry(IPB) to discover the molecular (分子) process of plant growth. In Current Biology, a scientific journal, they presented their findings on high-temperature plant growth. This could lead to developing plants that can survive global warming.

Plants react to even small temperature changes, but they are unable to move to new locations. “When temperatures rise, plants grow taller ... to cool themselves off. Their stems become taller, and their leaves become narrower and grow farther apart. Yet, this makes the plant more unstable overall,” explains Professor Marcel Quint, an agricultural scientist at MLU. Unstable plants bend faster in the rain and produce less food that’s also less nutritious.

There’s still lots to learn about plant reactions to temperatures. “We are just starting to understand how plants feel the changes in temperature ...,” Quint says. Earlier studies have shown that the protein (蛋白质) PIF4 directly controls plant growth and is also dependent on temperature. When it’s cold, PIF4 is less active, meaning the plant doesn’t grow. At higher temperatures, PIF4 activates growth-promoting genes, and the plant grows taller. This is new information, says Quint.

To understand it, they studied the growth of thale cress (拟南芥) seedlings. Normally, its seedlings form short stems at 20℃. These stems become much longer at 28℃. They discovered a hormone (荷尔蒙) that activates the PIF4 at high temperatures, thus producing the protein.

The findings may help to develop plants that remain stable even at high temperatures and produce many crops.

A．Farmers.	B．Teachers.
C．Researchers.	D．Environmentalists.

10 . In 2018, Pakistan promised to plant ten billion trees in an effort to slow climate change and to save a land that has been destroyed.

That program, whose name is 10 Billion Trees Tsunami, has been taking effect slowly for the past two years, but it recently has received unexpected help from the coronavirus(新冠病毒). Many Pakistanis are suddenly unemployed, so the government has given them jobs as tree-planters. Unemployed day laborers have been turned into "jungle workers", planting trees for 500 rupees a day($3). It's not much, but it can help the unemployed get by.

As the coronavirus struck Pakistan, the 10 Billion Trees campaign was halted as part of social distancing orders put in place to slow the spread of the virus. But earlier this month, the government allowed the forestry agency to restart the program and create more than 63, 600 jobs.

The program is employing three times the number of planters as it normally does, and the planting season has been extended from May(its usual end)throughout June, in order to keep workers employed. All workers are being told to wear masks and keep two meters of distance from others.

Shahid Rashid Awan, project director for Punjab province, said the project hopes to reach 50 million trees this year. “We can absorb all the unemployed laborers and workers who have fled the cities and returned to their villages in the past few weeks.”

A study declared tree planting to be an effective way to store carbon, and if planted in large quantities around the globe, a powerful solution to climate change. While it won’t fix every climate-related problem we have, it can go a long way if done widely, which is exactly what Pakistan is trying to do with such impressive determination.

And the workers will benefit greatly, too. Not only are they able to earn money and support their families at a difficult time, but they’re outside in the fresh air, away from the potential health risks from more tightly-packed urban environments. It’s a brilliant idea that all country leaders should consider copying.