【推荐1】Animals, including humans, feel sound as well as hear it, and some of the most meaningful communication happens at frequencies (频率) that people can’t hear. Elephants, for example, use these low-frequency sounds to, among other things, find family or a mate across long distances. Whales do it, too.

But you don’t have to weigh a ton to make a sound. In fact, you don’t have to be bigger than a pea. Consider, for example, the tree-hopper, a curious little animal that lives on the stems (茎) of the leaves. University of Missouri biologist Rex Cocroft has spent much of his time listening closely to tree-hoppers with his team.

The team discovers that all the sounds being heard from tree-hoppers are produced by males. They do it by vibrating (振动) their abdomens (腹部) to make a wide variety of strange sounds. There is almost no airborne sound produced with these vibrational sounds. Cocroft explained, “If a tree-hopper were to stand on your finger and produce a sound, you would feel the vibration but hear no sound.”

They showed that some sounds, not surprisingly, seem to be aimed at attracting females. And some are aimed at other males.

Cocroft explained, “When two males meet each other, or when they are mate-searching on a branch, we’re hearing ‘purring, bdddddrrrr…’ sounds that males give.” Normally, a person couldn’t hear any of this, because the sound travels along the stem, inside it. And that’s how other tree-hoppers detect it.

Cocroft said tree-hoppers have very sensitive legs. And they stand around on stems, which are good at spreading vibrations. So they just use what nature gives them to communicate with each other.

“They have so many different forms of social behavior and grouping,” Cocroft explained. “And once there are animals living in groups, then there will be all sorts of interesting possibilities for communication.”

【推荐3】How to Care for a Pet Fish

Taking care of a pet is a big responsibility, so you should make sure you learn all about your pet before bringing it home.    1     That's because fish can give them a good idea of whether or not they'll be able to take care of a more complicated (复杂的) pet later on.

First, choose what types of fish.     2     They are easier to raise and give you enough experience to take care of fish and their tanks (水箱). Some kinds of fish do not get along with others, so you'll need to choose what kinds to buy.

Next, make sure you have all of the necessary supplies. Fish need a fish tank. Make sure it is big enough for the number of fish. Fish tanks need a light and some machines to keep the water clean and at a comfortable temperature.    3    

Now you can set up your aquarium (水族馆). Wash sand and decorations (装饰物) clean and fill the bottom of the tank with them.     4     Follow the instructions on the heater to heat up the water to the temperature your fish will need. Make sure your light is ready to go, too!

    5     The pet store keeper can teach you how to make your fish get comfortable before you put them into your aquarium. Once the fish are in the tank, you have to watch them closely to make sure they don't get sick. Feed them in small amounts a few times a day. You will have to change some of the water at least once a week.

【推荐1】Low pay, uncertain jobs and debt mean young people are being hard hit by the UK’s financial crisis. In January this year a major survey showed that 47% of under-24s were viewed as “financially uncertain”—unable or only just able to make ends meet.

The survey was carried out last year before the reality of 2022’s cost-of-living crisis had started to unfold. We wanted to find out what young people’s money worries are and how to deal with them. A recent survey found 3 in 10 young people worry about not having enough money over a typical month. Only 51% of 16-and 17-year-olds in the UK feel confident about dealing with money.

And an increasing number of young people are returning to the Internet for tips. “There was a lack of support in my community and secondary school”, says Zoya. Unluckily, Zoya isn’t alone and millions of young people are struggling to access the information they need, both within the structures of school and at home with family.

Although some factors in the cost-of-living crisis are out of our hands, there are steps everyone can take. Here are our top tips. Set a budget (预算). Once you have a clear idea of the money that you use, you know how much money you have left to set apart and spend in other areas of your life. Check your basket. Thinking ahead about your meals and writing down a shopping list can give you a better chance of sticking to your budget. Get a budgeting partner. Set aside 10 minutes each week to check in with a friend or a family member, track your spending and share your moneysaving methods. Learn good habits. Some financial respected experts can bring free courses to help people build financial security to help young people.

【推荐2】Nearly two years after the COVID-19 outbreak, China has granted approval to its first antibody combination therapy (治疗) for COVID-19 treatment, adding a tool to the world’s fight against the disease.

A team from Tsinghua University, along with the Shenzhen People’s Hospital, has accomplished the task in 20 months. It would usually take 10 years. “It can reduce the rate of hospitalization (住院治疗) and death by 80 percent,” said Zhang Linqi, leader of the research team.

The new antibody drug is immediately effective after being used. Moreover, the therapy can protect people, especially those whose physical condition doesn’t allow vaccination (接种疫苗), from becoming infected by COVID-19 for around 9 to 12 months, said Zhang.

How does it work? When a virus infects a cell, it relies on an important type of protein: the spike proteins (棘突蛋白) on its surface. The spike proteins serve as a key to unlocking a cell. If a virus cannot enter a cell, it will disappear immediately. The job of our antibodies is to block the virus from entering cells. So its target is very precise. In addition, thanks to the coordination between the two antibodies, it is highly efficient in preventing the virus, according to Zhang. The qualities of the new drug make it especially useful for high-risk groups, such as frontline medical workers and people not suitable for vaccination due to various underlying health problems.

The new drug is expected to come to the market soon, but it’s not cheap. That’s because of limited production. Noting that China has used science and technology to fight COVID-19 since the beginning of the outbreak, Zhang said, “Science is the key to solving the issue. Science has shown its power in all sectors, from medical treatment, medicine and vaccine development to prevention and control measures.”

【推荐3】On July 11th Virgin Galactic finally realized the promise that it would take passengers on life-changing trips in its spaceships. For 4 minutes, its six temporarily weightless passengers, including the firm's co-founder, Sir Richard Branson, saw the planet's curvature (曲度) against the blackness of outer space. He may have gloated (窃喜) over beating Jeff Bezos（much richer）, Amazon's retired boss, who would go slightly higher, for slightly less time, in a vehicle built by his own company, Blue Origin, on July 20th.

The two are among a growing group of enthusiasts who believe space tourism's time has come. Suborbital (亚轨道) tourism is part of a broader space economy that has boomed over the past decade thanks to technological advances. Those at Morgan Stanley expect the entire space economy to generate$1trm in revenue by 2040, from $350bn today. UBS (瑞银集团) expects the entire space economy to produce $800 billion by the end of this decade. Space tourism，it thinks, will make “a big contribution” to that total.

But that is highly unlikely. For example, space tourism is not even Blue Origin's main goal. The company is focusing on developing a large new rocket for launching satellites, on selling advanced rocket engines to other companies and on winning NASA contracts such as that for a system to land humans on the Moon. In the long run, Mr Bezos doesn't see Blue Origin as provider of services to thrill-seekers.

The business could be profitable once regular flights begin to offset (抵消) the rockets' development costs. But how fast and by how much is uncertain. Without tourist-friendly destinations to visit, space tourism, with its far higher ticket prices, will not be a huger earner.

Another challenge—and the biggest uncertainty—relates to safety. History has shown that a disaster can set progress back by years. Even with no accidents, problems may arise. Strict top down regulation could mean that industry will no longer have the freedom to pursue new approaches to improving safety.

Space tourism may remain a hobby for a few superrich with a desire to take risks and lots of time to spare. Not exactly a mass market, then, for the time being.