3 . We should all have at least one fire extinguisher somewhere in our home, but it’s not enough to simply keep one under the kitchen sink. If there is a fire, your safety — and the safety of your home — depends on knowing how to use that fire extinguisher correctly. In case your fire extinguisher has been sitting around collecting dust, here’s everything you need to know before brushing it off and fighting a fire in your home the right way.

Choose the right fire extinguisher

The first thing you need to know is the different classifications of fires. Most household fires fall into one of the following categories:

Class A: Fires fueled by solid combustibles like wood, paper, and cloth.

Class B: Fires fueled by flammable liquids such as oil and gasoline.

Class C: Fires started or fueled by faulty wiring and appliances.

Class D: Fires started or fueled by cooking oils, animal facts, and vegetable fats.

All fire extinguishers are labeled to indicate which classes of fire they are designed to combat. Most household fire extinguishers are considered multipurpose and labeled for use in A, B, and C classes. Class K extinguishers are heavier duty and will need to be bought separately. Household fire extinguishers are also rated for the size of fire that they can safely handle. The higher the rating, the larger the fire the extinguisher can put out. Higher-rated extinguishers are often heavier.

Steps for proper extinguisher use

Once you understand the different types of fire extinguishers and their uses, you need to be able to properly operate one.

Before operating the fire extinguisher, make sure you have a clear evacuation path. If you cannot put out the fire, you’ll need to make a safe exit. Also, make sure everyone else is being evacuated from the building.

Even if the fire appears manageable, you should always have the fire department on the way. Once firefighters arrive, they can double-check whether the fire has been completely extinguished.

Face the fire and keep your back to the clear exit. You should stay between 1.8 and 2.5 meters away from the flames as you prepare to operate the fire extinguisher.

It can be difficult to think clearly during an emergency. Thankfully, there is a long-standing acronym(首字母缩略词)— PASS — to help you recall the steps involved in operating your fire extinguisher.

P: Pull the pin (保险销) on the fire extinguisher.

A: Aim low. Point the nozzle at the base of the fire instead of the flames.

S: Squeeze the handle or lever to discharge the extinguisher.

S: Sweep the nozzle back and forth until the flames are extinguished.

After the flames appear to be out, continue to watch the fire area to make sure it doesn’t reignite. If the fire does start up again, repeat the “PASS” process.

Once the fire is out, or if you are unable to put it out, leave the scene. Find a place out of reach of the fire.

4 . Gone are the days when big businesses were looked upon by environmentalists as enemies in the fight against global warming.

Just two weeks after U. S. President Donald Trump pulled his country out of the Paris Climate Agreement, more than 900 American firms put their _______to a “We Are Still In” open letter to the United Nations. Together, they promise to help reduce America’s carbon emissions by 26 percent by 2025, _______the Paris Climate Agreement.

_______, big businesses have been taking climate change seriously for years now. Alongside energy-efficiency measures, the strongest evidence of their _______has been the number of new wind and solar projects that they have been helping to build around the world. IT firms such as Amazon and Google have been using clean energy to power their servers (服务器). Some environmentalists now believe that big businesses could become strong _______behind the worldwide spread of renewable energy. “There used to be little action,” says Marty Spitzer of the World Wildlife Fund (WWF), “Now, I see fundamental _______being made.”

More recently, this enthusiasm for environmental protection has _______from corporate headquarters to branches and suppliers, and from developed countries to emerging markets. Take Walmart, the world’s largest retailer, for example. In March 2016, it said that it would require its own operations and those along its _______chain to reduce carbon-dioxide emissions by one billion tons by 2030. This is _______to taking 211 million passenger cars off America’s roads for a year. The announcement was ________by the WWF and other conservation organizations, which are helping Walmart’s suppliers work towards this goal. Apple, maker of the iPhone, has said that seven of its biggest global manufacturers have promised to power their Apple-related ________with renewable energy by the end of this year.

According to the WWF, in the United States alone, nearly two dozen of the biggest firms have committed themselves to becoming 100 percent renewable in the near future. Hervé Touati of the Rocky Mountain Institute, a clean-energy research firm, explains the ________behind this trend. Going green improves the companies’ public image and helps attract customers, staff and investors.

Anheuser-Busch InBev, the world’s biggest brewer (啤酒公司), has lots of young people among its many ________. Many of them take environmental issues seriously. Electricity, used ________in the brewing process, amounts to a tenth of its total costs. Last year, the company set out to increase the role of renewables in generating ________to 100 percent by 2025. “My generation often takes energy and clean air for granted,” said Tony Milikin, the firm’s chief sustainability officer. “The generation coming up now looks at it totally differently.”

5 . A recent study published in the journal Science Advances has revealed that the United States ranks as high as third among countries contributing to coastal plastic pollution. The new research challenges the once-held assumption that the US is adequately “managing” its plastic waste. A previous study using 2010 data that did not account for plastic waste exports had ranked the US 20th, globally, in its contribution to ocean plastic pollution.

Using plastic waste generation (产生) data from 2016 — the latest available global numbers — scientists calculated that more than half of all plastics collected for recycling (1.99 million tons of 3.91 million tons collected) in the US were shipped abroad. Of this, 88% of exports went to countries struggling to effectively manage plastics; and between 15-25% was low-value or contaminated (受污染的). It means it was unrecyclable. Taking these factors into account, the researchers estimated that up to 1 million tons of US-generated plastic waste ended up polluting the environment beyond its own borders.

Using 2016 data, the paper also estimated that between 0.91 and 1.25 million tons of plastic waste generated in the US was either littered or illegally dumped into the environment domestically. Combined with waste exports, this means the US contributed up to 2.25 million tons of plastics into the environment. Of this, up to 1.5 million tons of plastics ended up in coastal environments. This ranks the US as high as third globally in contributing to coastal plastic pollution.

“The US generates the most plastic waste of any other country in the world, but rather than looking the problem in the eye, we have outsourced it to developing countries,” said Nick Mallos, senior director of Ocean Conservancy’s Trash Free Seas program and a co-author of the study. “The solution has to start at home. We need to create less, by cutting out unnecessary single-use plastics; we need to create better, by developing innovative new ways to package and deliver goods; and where plastics are inevitable, we need to greatly improve our recycling rates.”

“Previous research has provided global values for plastic input into the environment and coastal areas, but detailed analyses like this one are important for individual countries to further assess their contributions,” said Dr. Jenna Jambeck, Distinguished Professor at the University of Georgia’s College of Engineering and a co-author of the study. “In the case of the United States, it is critically important that we examine our own backyard and take responsibility for our global plastic footprint.”

6 . Humans are not the only ones who underwent self-domestication. So did our close relatives, the bonobos, and the species we call our best friend. A tiny proportion of the genome differentiates dogs from wolves, and yet millions of dogs are comfortably curled up in our homes, while wolves move around at the edge of extinction.

When our research group began its work almost 20 years ago, we discovered that dogs also have extraordinary intelligence: they can read our gestures better than any other species. Wolves, in contrast, are mysterious and unpredictable. Their home is the wilderness, and that wilderness is shrinking.

But not so long ago the evolutionary race between dogs and wolves was so close, it was unclear who would win. Dogs, in fact, did not descend from wolves. Instead, dogs and wolves shared a wolflike ancestor.

Folklore supposes that humans brought wolf puppies into camp and domesticated them. Or as wolf expert David Mech wrote in 1974, “Evidently early humans tamed wolves and domesticated them, eventually selectively breeding them and finally developing the domestic dog from them.” But this story has not held up. Taming an animal occurs during its lifetime. Domestication happens over generations and involves changes to the genome.

So how did wolves turn into dogs? Back in the Ice Age, as our human populations grew more sedentary, we probably created more rubbish, which we then dumped outside our camps. These leavings would have included tempting pieces of food for hungry wolves. Not every wolf would have been able to scavenge, however. These animals would have had to be unafraid of humans, and if they displayed any aggression toward us, they would have been killed. After generations of selection for friendliness without intentional selection by humans, this special population of wolves would have begun to take on a different appearance. Coat color, ears, tails: all probably started to change.

Animals that could respond to our gestures and voices would be extremely useful as hunting partners and guards. They would have been valuable as well for their warmth and companionship, and slowly we would have allowed them to move from outside our camps to our firesides. We did not domesticate dogs. The friendliest wolves domesticated themselves.

8 . Shining just 12 light-years from Earth, the star Tau Ceti so resembles the sun that it has appeared in numerous science- fiction stories and was the first star astronomers ever searched for signs of intelligent life, half a century ago. In 2012 Tau Ceti grew still more interesting when astronomers reported five possible planets somewhat larger than Earth circling closer to the star than Mars orbits (围绕……运动) the sun—one of which is in the star’s habitable zone. Newly released images taken by the Herschel Space Observatory provide even more insight about Tau Ceti’s solar system: greater detail about its dust belt.

Dust arises when asteroids and comets (小行星和彗星) crash into one another, so its location reveals where these dust- creating objects—which are too small to be seen directly—orbit a star. In Tau Ceti’s case, “it’s quite a wide dust belt,” says Samantha Lawler of the University of Victoria in British Columbia. As her team reported in November, the belt’s inner edge is roughly two to three astronomical units (AUs) from the star, which is the position of our own sun’s asteroid belt. (An AU is the distance from Earth to the sun.) Tau Ceti’s dust belt extends out to 55 AU, which would be just beyond our system’s main Edgeworth-Kuiper belt, the zone of small bodies whose largest member is probably Pluto. Presumably full of asteroids and comets, Tau Ceti’s dust belt most likely lacks a planet as large as Jupiter, Lawler says. The gravity of such a massive planet would have driven away most small space rocks.

Within a year a new series of radio telescopes in Chile called ALMA should provide a sharper view of the disk, especially of its inner edge. The ALMA images will help astronomers confirm whether the star’s five proposed planets are indeed real. If the disk overlaps the planets’ hypothesized (假设的) orbits, then they probably do not exist; they would have kept away most asteroids near the star, removing the source of dust.

If those planets do exist, however, Lawler’s team suggests that Tau Ceti’s planetary system may resemble what our solar system would have looked like had the four giant planets—Jupiter, Saturn, Uranus and Neptune- never formed: small planets orbiting close to the star, and nothing but asteroids, comets and dust beyond.

9 . The Delight of Bird-watching

It is springtime, and the city feels especially glorious. If we were to reflect on what has brought us joy during this challenging time, birds would probably be enjoying a top ________ on the happy list for many. Especially those we saw outside of our windows - or, in New York City, on the street.

Three species in particular ________ the sidewalks, tops of buildings, fire escapes, window ledges, and air conditioners: house sparrows, pigeons and starlings (椋鸟). All of these species are ________. When these species were first introduced, the scientific fields of ecology (生态学) and conservation were ________ nonexistent, and now we know that for pest control (虫害防治), this was a terrible idea. But I would add a qualifier to that terrible idea by calling it “a wonderful, awful” idea.

I have been studying starlings in New York City since 2016. I do so formally in museums and labs, but in between my research I watch them ________ on the street. I was initially fascinated by their adaptability to the ________ landscape, especially their ________ flexibility. They will eat a pile of yellow rice on Columbus Avenue, a soft pretzel on Central Park West, and a flattened apple pie in the parking lot of a Costco in Queens. Pigeons and house sparrows often hover and hop around them, but cannot compete with their ________. For a bird, they are good at walking on the ground.

The sounds they make are so ________ that you might not recognize that they are coming from the same species. If you listen closely, you can hear their up-and-down whistling, whirring, and even an early video game laser-like sound. You may not consider it ________ enough to be called a song, but it is a song nonetheless. When you stare at them, as I have many times, they never even appear to look at you, but they obviously see you because they respond incredibly rapidly to absolutely any movement or disturbance. They are off ________, always faster than I can draw my phone out in order to grab a good picture.

Sometimes, I wish that I did not know about what else they do across the country, and could just enjoy watching them in a quiet ________. And I wonder if you can know about their paths of ________ and still appreciate aspects of their behavior.

At times this winter, nothing in the built environment even came close to ________ me of life or the natural world. And then way up in that bit of sky, beside the water tower, I spotted five of them. I’d know their triangular wings, and their quick and suspicious behavior, anywhere. As they flew up and ________, they left in their wake the hope of bluer skies and future springtime.

10 . The older of two sisters, Jane Goodall was born on April 3, 1934, in London, England, into a middle class British family. When Goodall was about two years old, her mother gave her a toy chimpanzee, which Goodall still possesses to this day. She was a good student, but she had more interest in being outdoors and learning about animals. Once she spent five hours in a hen-house so she could see how a hen lays an egg. She loved animals so much that by the time she was ten or eleven she dreamed of living with animals in Africa. Her mother encouraged Goodall's dream, which eventually became a reality.

When Goodall was eighteen she completed secondary school and began working. She worked as a secretary, as an assistant editor in a film studio, and as a waitress, trying to save enough money to make her first trip to Africa.

Jane Goodall finally went to Africa when she was twenty-three years old. In 1957 she sailed to Mombasa on the east African coast, where she met anthropologist (人类学家) Louis Leakey (1903-1972), who would become her mentor, or teacher. In Africa, Leakey and his wife, Mary, had discovered what were then the oldest known human remains. These discoveries supported Leakey’s claim that the origins of the human species were in Africa, not in Asia or Europe as many had believed.

Leakey hoped that studies of the primate (灵长目动物的) species most closely related to human beings chimpanzees, gorillas, and orangutans — would shed (散发) light on the behavior of the human animal’s ancestors. He chose Goodall for this work because he believed that as a woman she would be more patient and careful than a male observer and that as someone with little formal training she would be more likely to describe what she saw rather than what she thought she should be seeing.

Later Goodall turned her attention to the problem of captive (被囚禁的) chimpanzees. Because they closely resemble humans, chimpanzees have been widely used as laboratory animals to study human diseases. Goodall used her knowledge and fame to work to set limits on the number of animals used in such experiments and to convince researchers to improve the conditions under which the animals were kept. She also worked to improve conditions for zoo animals and for conservation of chimpanzee habitats. In 1986 she helped found the Committee for the Conservation and Care of Chimpanzees, an organization dedicated to these issues. She has even written children’s books, The Chimpanzee Family Book and With Love, on the subject of treating animals kindly.

For her efforts Goodall has received many awards and honors. In 2000 she accepted the third Gandhi-King award for Non Violence at the United Nations. She does not spend much time in Africa anymore; rather, she gives speeches throughout the world and spends as many as three hundred days a year traveling.