Human memory is notoriously (众所周知地) unreliable. Even people with the sharpest facial recognition skills can only remember so much.

It’s tough to quantify how good a person is     1     remembering. No one really knows how many different faces someone can recall, for example, but various estimates tend to hover in the thousands – based on the number of acquaintances a person     2     have.

Machines aren’t limited this way. Give the right computer a massive database of faces, and it can process what it sees – then recognize a face it     3     (tell) to find – with remarkable speed and precision. This skill is     4     supports the enormous promise of facial-recognition software in the 21^st century. It is also what makes contemporary surveillance (监控) systems so scary.

The thing is, machines still have limitations when it comes to facial recognition. And scientists are only just beginning to understand what those constraints are.     5     (figure) out how computers are struggling, researchers at the University of Washington created a massive database of faces – they call it MegaFace – and     6     (test) a variety of facial-recognition algorithms(算法) as they scales up in complexity. The idea was to test the machines on a database that included up to 1 million different images of nearly 7,000 different people – and not just a large database     7     (feature) a relatively small number of different faces, more consistent with what’s been used in other research.

As the databases grew, machine accuracy dipped across the board. Algorithms     8     were right 95% of the time when they were dealing with a 13,000-image database, for example, were accurate about 70% of the time when     9     (face) with 1 million images. That’s still pretty good, says one of the researchers, Ira Kemelmacher-Shlizerman. “Much better than we expected,” she said,

Machines also had difficulty adjusting for people who look a lot alike –either doppelgangers (长相极相似的人), whom the machine would have trouble       10     (identify) as two separate people, or the same person who appeared in different photos at different ages or in different lighting, whom the machine would incorrectly view as separate people.

2 . A huge crowd has gathered to watch China’s new scientific research ship enter the water for the first time. This ship, equipped with on-board labs and the latest scientific kit, will eventually explore the world’s oceans. But it is also going to help China plunge beneath the waves: it will serve as a launch-pad for submarines that can dive to the deepest parts of the ocean. “Humans know much less about the deep oceans than we know about the surface of the Moon and Mars. That’s why I want to develop the facility for ocean scientists to reach the deep seas,” says Prof. Cui Weicheng.

He is the dean of deep sea science at Shanghai Ocean University but he has also set up a private company called Rainbow Fish, which built the new research ship and is busy developing submersibles. One of its unmanned subs reached a depth of 4,000m (13,000ft) in its most recent trial. But Rainbow Fish’s ultimate goal is manned exploration and it plans to take humans to the very bottom of the ocean the Mariana Trench, in the Pacific, at a depth of nearly 11,000m (36,000ft). He shows me around a life-size model of the submarine and explains that there is room inside for a crew of three, who will be protected by a thick metal sphere.”At the moment, we are in the design stage, so we are testing several extremely high-strength materials for it.” It will have to bear immense pressures from the crushing weight of water above. If there are any weaknesses, the submarine will implode. The deepest ocean is a place few people have ever experienced first-hand. The first dive to the Mariana Trench was carried out in 1960 by US Navy Lieutenant Don Walsh and Swiss engineer Jacques Picard. Their vessel, the Bathyscaphe Trieste, creaked and groaned as it made the descent, taking nearly five hours.

The only other manned expedition was carried out by Hollywood director James Cameron, who took a solo plunge in a bright green submarine in 2012. Rainbow Fish wants its sub to be next. The team insists its venture isn’t about politics and that it is looking to collaborate with American, Russian and European scientists. It is, though, a commercial operation. The company plans to charge people to use its research ship and submarines, and is targeting three groups, says managing director Dr. Wu Xin. “The first is definitely the scientists who are interested in studying deep-sea science and technology. The second group is offshore companies and oil companies. The last one is tourists and adventurers [who] want to go down themselves to have a look at what’s going on there,” he says. This kind of entrepreneurial approach may be a new model for science in China. Deep-sea research is a difficult, high-risk activity — and much of the ocean remains unexplored. But Cui, who hopes to be the first Chinese person to reach the Mariana Trench, believes that China could be the nation to truly open up this final frontier.

The Great Voice Actor

Since the creation of animated (动画的) motion pictures, the use of actors supplying voices     1    (be) invaluable. Behind every famous cartoon character’s personality is the actor standing in the recording booth and     2     (stretch) their manner of speaking in unrecognizable ways. For some of these performers, the voices they’ve provided have far surpassed them as people in both recognizability and adoration.

Mel Blanc, known as “The Man of Thousand Voices”,     3     (regard) as the most prolific actor to ever work in Hollywood with over a thousand screen credits. He developed and performed nearly 400 distinct character voices. Whether in legendary shorts or lesser-known commercials, Mel Blanc walked so the voice actors of today     4     run.

Mel Blanc lent his voice to many classic characters, but the one he is best known for is Bugs Bunny. There is little that can be said about Bugs’ impact     5     hasn’t already been said for decades. The character is     6     helped launch Warner Bros. animation into the mainstream. Bugs was even the face of Warner Bros. Family Entertainment, appearing at the beginning of many films.     7     a character may not talk, that doesn’t mean a fair bit of voice acting isn’t involved. Mel provided the various noises of the beloved pet dinosaur, Dino, in The Flintstones. While obviously not as quotable as his caveman companions, every fan knows the excited bark of Dino when he sees his master, Fred, arrive home. In January 1961, at the age of 52, Blanc was severely injured in a car accident and had to tape his part at home with a microphone     8     (suspend) over his bed.

Mel Blanc paved the way for voice acting as a true art, though it’s a skill that often goes unrecognized when praise is focused on movies and TV. The characters we all love wouldn’t be where they are in the public eye without     9     who put a voice to them. Many recognizable or popular voice actors of our modern era have Blanc     10     (thank) for their start, and hope to reach his level of unmatched expertise at bringing countless characters to life the way no one else can.

5 .

Zion National Park in Utah has plenty of trails, but Angels Landing may be the most breathtaking. Picture this. You begin the hike on the wide and well-maintained West Rim Trail. It follows the river and then crosses the bottom of the canyon, surrounded by 270-million-year-old layers of rock. Relaxing, right? Just wait for it. The trail then starts to climb via a series of switchbacks (急转弯) leading up the side of the mountain. Then more switchbacks: 21 tighter turns, called “Walter’s Wiggles,” where elevation levels rapidly increase. Your heartbeat is probably rapidly increasing at this point, too.

On top of Walter’s Wiggles, you can stop for a stunning view (perhaps with a marriage proposal) and a restroom stop while you contemplate (仔细考虑) the final stretch of the hike. If you’re afraid of heights, it’s best to turn back now. The last stretch is the real test of bravery.

The last half mile of the hike is what really ranks it as one of the nation’s most dangerous. Angels Landing itself is a fin-like formation jutting (突出) 1,500 feet out of the canyon, and this is where you make the final 500-foot climb. Guardrails and chains bolted (拴住) into the cliff help you keep from tumbling over the extremely steep ledge. You’re literally living on the edge, and you don’t want to trust the “angels” down there to catch you. Once you reach the top, however, it’ll all be worth it: 360-degree views of the canyon make a great backdrop for kicking back and having a meal before you come back down the way you came.

Angels Landing might be dangerous, but thankfully, not too many people have had fatal falls. According to the park website, seven people have died in the 100 years the park has existed. Still, this is a very vigorous hike. If you’re out of shape, bringing young children along, feel ill or prone to fainting, or are just plain afraid of heights, opt for an easier trail.

Angel’s Landing is a great hike for most of the year, besides the cold winter months when the trails could become dangerously slippery. Summer is the most popular time of year — and therefore the most crowded — but it can also get extremely hot, so opt for an early morning hike while the temperatures are still mild.

Sure, it’s dangerous, but there’s a reason this is one of Zion ‘s most popular hikes. If you’re up for the challenge, Angels Landing will definitely deliver rewards.

This article first appeared on Curiosity.com.

6 . Acupuncture(针灸), an ancient Chinese medical practice, has been the remedy for countless patients for thousands of years. Before modern medicine came to life, ancient Chinese used stone tools to ______ pain. Over time, this primitive practice ______ evolved into a comprehensive and profound medical system and ______ the root of acupuncture.

Acupuncture is a treatment that aims to ______ the body’s self-regulating functions. Its therapeutic principles are in line with the ______ concepts of traditional Chinese medicine, which emphasizes all-inclusive treatment, meridian(经络) adjustment, balance of bodily functions and overall physiological well-being.

Practices can ______ in forms, including needle insertion, cupping and scraping. Needle insertion, the most common method, is______ by inserting hair-thin needles into meridians, ______ specific points on the body that ______ vital energy (the qi). Practitioners lift, twirl and rotate needles to unblock the flow of energy; ______ yin and yang balance; and stimulate the body’s innate ______ to heal itself.

Looking beyond China, acupuncture has become a global ______. Over the years, acupuncture has seen many advancements in scientific research and modern medicine. It is now a mainstream ______ and complementary treatment for a variety of weaknesses. According to a 2019 WHO report, acupuncture is used in 113 of its 120 member countries, ______ its widespread recognition and application.

As an ancient Chinese medical ______ with a rich history and deep cultural significance, acupuncture is an embodiment of profound cultural heritage and a holistic path to healing.

8 . Have you ever had a song stuck in your head and, no matter how hard you tried, you could not get rid of it? The song played on and on, whether you were loading the dishwasher, weaving in and out of traffic, or attempting to _________ your mind at the start of yoga class.

Having a song stuck in one’s head, known as an earworm, is an experience that over 90% of us have on a _________ basis. We’re more likely to catch an earworm after we stop focusing, in moments when the working memory is _________, when we’re relaxed, when work is finished or when we’re a bit sleepy.

Certain songs are _________ than others, and so more likely to “auto repeat” in your head. There are certain musical characteristics that make songs more likely to become earworms, such as if the piece is repetitive, if there is a longer duration of certain notes, if _________ between the notes are smaller. _________, we know that mood can have an impact, with some people reporting that they always get the same earworm when they feel good, or people experiencing a fast-tempo earworm when they are _________. And of course familiarity with a song is a key _________. Songs that you don’t know very well are less likely to pop up as earworms.

If you’ve had enough of your earworm and need to stop it in its tracks, you would be well warned not to try to block the song out, but rather to _________ accept it. A determined effort to block the song out may result in the very __________ of what you want. According to psychologist Daniel Wegner, __________ the song may make your brain keep playing it over and over again. To get rid of an earworm, you may be best served by simply __________ it, accepting it, and leaving it alone to let this phenomenon ends up weakening itself little by little.

Some people try to __________ themselves from the song, and it works. You can try reading a book, listening to a different song or even playing an instrument. Others __________ the tune in question, because it is commonly believed that earworms occur when you remember only part of a song; hearing the entire song may stop it. Neurologists (神经学家) point out that it’s recommendable to chew gum to reduce the __________ of an earworm because jaw movement interferes with musical memory. However, it’s important to note that this phenomenon usually lasts less than 24 hours.