On the eve of our daughters' weddings, I gave both of them what Iconsidered to be excellent marital advice: never leave your husband unsupervised(无人监督的) with pruning shears (修枝剪).

If only I had taken my own advice. I recently let my guard down. Thirty-some years of marriage can do that toa woman. Give a man pruning shears and electric trimmers (电动修剪器) and he will givenew meaning to “armed and dangerous.”

One day earlier this year, my husband saidthat the crab apple tree was dead.

“Why do you think it is dead?” I asked.

“Look at it. There's not a leaf on it.”

“There's not a leaf on anything. It'sMarch,” I said.

“It looked sick last fall and with thisbitter winter we had, I'm convinced it's dead.”

The truth is he's never liked thecrabapple. Sure, it has beautiful blooms in the spring, but then it gets adisease, the leaves curl, and it drops those little apples that sit on thedriveway.

Each passing week he pronounced the treedead. Eventually I began to believe him. Though he agreed it would be aregrettable loss, there was a twinkle in his eye. He armed himself a couple ofweeks ago and began trimming. A branch here, a branch there, a small limb, thena large limb. I watched and then decided to check the wood on some of thebranches closer to the trunk. I broke one off and saw green.

The crabapple was not dead. It just hadn'thad time to leaf out. The tree was now falling to one side, but it was notdead. I would have told him so, but he had moved on to a maple. Once the manstarts, he can't stop. One trim leads to another.

“Please, stop!” I called.

He smiled and nodded, but he couldn't hearbecause he had started the hedge (树篱) trimmers and was getting ready to fix a line of hedges.

Zip (飕飕声), zip, zip.

“What do you think?” he shouted.

“It's supposed to be a privacy hedge; nowall that will be private are our ankles.”

He started the trimmers again.

“Stop!” I called, “Come back!”

“Why?” he shouted.

“You're in the neighbor's yard.”

    Why do human beings still risk their lives under ground and doing one of the dirtiest and most dangerous jobs in the world? It is an increasingly urgent question, given the recent mining accidents in Sago, W. Va and Huntington, Utah. A small group of engineers and robotics experts look forward to a day in the not-too-distant future when robots and other technology do most of the dangerous mining work.

    Robotic technology, in particular, holds much promise, McAteer says, especially when it comes to mapping mines and rescuing trapped miners — the special operations of the mining industry.

    One of the first mining robots was developed five years ago at Carnegie Mellon University's Robotics Institute. It was called Groundhog. It used lasers(激光器) to “see” in dark tunnels and map abandoned mines—some of the most dangerous work in the business.

    The latest design is called Cave Crawler. It's a bit smaller than Groundhog, and even more advanced. It can take photos and videos and has more sensors that can detect the presence of dangerous gases. Incredibly, the robot has a real sense of logic. If it comes across an obstacle it gets momentarily confused. It has to think about what to do and where to go next. Sometimes it throws a fit just like a real person.

    The greatest problem, though, is cost. The money of the earliest research project was provided by the government, but that money had dried up, and it's not clear where future money will come from. Partly for that reason, and partly because of advances in safety, mining is not nearly as dangerous as it was in the past. Since 1990, fatalities(致命性) have declined by 67% and injuries by 51% , according to the National Mining Association.

    Some experts predict that robots in mines will serve much of the same function that they do in the automotive industry. The robots do the most boring and dangerous jobs，but won't get rid of the need for human workers.

    World Elephant Day is the perfect time to find out more about these amazing animals and what we can do to preserve them so they do not go the way of the mammoth（猛犸象）.

    World Elephant Day was created in 2011 by two Canadian filmmakers Patricia Sims and Thailand's Elephant Reintroduction Foundation and was first celebrated on August 12, 2012. They made the documentary Return to the Forest, a fascinating 30 minute film about the reintroduction of caught Asian elephants to the wild.

    Currently, the demand for ivory（象牙）is becoming bigger and bigger, whose price is higher than that of gold, making elephants bigger targets than ever. Habitation loss is also a danger to the world's elephant population as it robs elephants of the hundreds of pounds of food they need every day, making it more difficult for them to breed and making it easier for hunters to track them down. Circuses and tourism are also serious threats to the animals' well-being.

    The best way to celebrate this day is to take the opportunity to educate yourself about these magnificent（巨大的）mammals and share your knowledge with others. As ever, simply spreading the word about the dangers these magnificent mammals face via social media can actually make a real change. Expose that “training” elephants often involves tying and beating them daily for months on end. If you want to get a bit more involved, you could choose to make a donation to a foundation dedicated to protecting elephants from hunters or relocating them to locations better suited to their needs.

    Whichever way suits you best, make sure that you spend this day in a way that helps elephants all over the world, so we, in turn, can continue to wonder at them and their uniquely fascinating way of life.

    Once when I was facing a decision that involved high risk, I went to a friend. He looked at me for a moment, and then wrote a sentence containing the best advice I've ever had: Be bold and brave and mighty (强大的) forces will come to your help.

    Those words made me see clearly that when I had fallen short in the past, it was seldom because I had tried and failed. It was usually because I had let fear of failure stop me from trying at all. On the other hand, whenever I had jumped into deep water, forced by courage or circumstance (环境), I had always been able to swim until I got my feet on the ground again.

    Boldness means a decision to bite (咬) off more than you can eat. And there is nothing mysterious about the mighty forces. They are inner powers we have: energy, skill, sound judgment, creative ideas––even physical strength greater than most of us realize.

    Admittedly, those mighty forces are spiritual ones. But they are more important than physical ones. A college classmate of mine, Tim, was an excellent football player, even though he weighed much less than the average player. “In one game I suddenly found myself facing a huge player, who had nothing but me between him and our goal line,” said Tim. “I was so frightened that I closed my eyes and crazily threw myself at that guy like a bullet (子弹) ––and stopped him cold.”

Boldness—a willingness to get yourself to the extreme—is not one that can be gained overnight. But it can be taught to children and developed in adults. Confidence builds up. Surely, there will be setbacks (挫折) and disappointments in life; boldness in itself is no guarantee (保证) of success. But the person who tries to do something and fails is a lot better off than the person who tries to do nothing and succeeds.

    So, always try to live a little bit beyond your abilities — and you'll find your abilities are greater than you ever dreamed.

Earthworms don't move fast. But humans can accelerate the worms' spread. Fishermen often use invasive(蔓延性的) earthworms to catch fish. Many have introduced invasive earthworms to rivers, streams and lakes previously unexposed to these animals. Gardeners who use earthworms to make their soil rich may unknowingly introduce invasive ones. The worms even give rides in the mud on wheels, potted plants and road materials shipped around the nation.

But they're not everywhere yet. In the Great Lakes region, "20 percent of the land is earthworm-free," says Cindy Hale, a research biologist. Of the remaining 80 percent of land, half of the land has fewer than two earthworm species-meaning there isn't yet too much impact on the ecosystem, she explains. For these regions, she says, now is the time to take action. According to Hale, educating the public, especially fishermen, is one approach to stopping the spread of invasive earthworms. Identifying which lands are currently earthworm-free is another.

Ryan Huefimeier, a program coordinator for Great Lakes Wom Watch, has been working on a model that will help create large maps of areas with minimal(最小的) or no damage from earthworms. Ultimately, landowners can use it to identify earthworm activity on their property. once identified, lands with minimal or no earthworm damage should be protected.

But scientists suspect that once invasive earthworms arrive they can't be removed. And even if all could be, affected forests might never return to the way they were. "It's very much a story of learning to live with them," concludes Lee Frelich of the University of Minnesota's Center for Forest Ecology.

Forest ecologists have called earthworms "ecosystem engineers" because they can change or create habitats that otherwise would not be present. Whether this is a good thing depends on the situation.

"What the earthworms do and how we value it is what really matters." said Hale. "In one place-farm fields or gardens-we really like European earthworms and what they do, so we consider them good. In native hardwood forests, we really don't like what they do-so we consider them bad. You really have to understand how an organism(微生物) affects an ecosystem. Things aren't black and white."

Edward Ndiritu joined Lewa Wildlife Reserve in central Kenya in 1996 as a rhino monitor. Back then, illegal hunting had greatly reduced the country's black rhino population. Worried that they might become extinct, he worked his way up to lead Lewa's anti-hunting team. In 2015, his team's community-focused conservation method won him the first Wildlife Ranger Award from conservation charity Tusk.

He grew up in a village between Mount Kenya and the Aberdare Forest, which was once a wildlife route for migrating elephants and black rhinos. He saw them disappear gradually. He realized that hunting and the disruptive actions of the community were the reasons. The demand for rhino horn(角), which is very valuable in Asia, drives hunters. They are part of a big and rich crime network. There are people who help them by giving them equipment. In 2011 and 2012, Lewa had many difficulties. They lost rhinos. It was found that those involved in hunting were also linked to human smuggling(走私) and other illegal activities.

The hunting challenge has changed. Hunters now have networks, get information from the local community, and use technology like phones and motorbikes. Edward's team has adapted by using cameras, sensors, trackers, and a system that tells them when and where hunting might happen. They also work closely with the community, which is now the first 

line of defense. Lewa gives agricultural training, medical help, and business support to rural women. This makes locals more likely to report hunting before it happens.

To be a good forest guard, one needs to be honest, tough, and motivated. Edward now knows that making sure the forest guards are happy and well is very important. He is hopeful about wildlife conservation in Lewa. Funding is a problem, but organizations like Tusk are helping. Conservation is about people. Looking after those outside the reserve is necessary for the future of wildlife. Only when communities can live in harmony with the animals they see every day will there be a good future for wildlife.