What do you use to unlock your cellphone? A password? A fingerprint? Or simply a glance?

    On September 12, 2017, Apple introduced its iPhone X, which has an eye-catching feature—Face ID.

    With Face ID, Apple says, you can unlock your new iPhone by just looking at it. It is powered by a so-called TrueDepth camera system built into the front of the iPhone X.

    When the camera system sees a person's face, it uses 30,000 unseen dots to “map” the shape and outline of the face. A mathematical model of the face will then be created and stored in the phone.

    The next time the person looks at the iPhone X, the same dots are mapped onto his or her face and compared to the stored model. If the two match, then the phone unlocks. This happens in less than a second.

    Apple says the system is smart. If you change your hairstyle, put on sunglasses or makeup, or use the phone in the dark, Face ID still works.

    Although the technology sounds fancy, there are still concerns. For example, will Face ID work for twins?

    According to Apple, the chance of others to unlock your iPhone X using Face ID is one in a million. Face ID can tell the difference between twins, but the error rating（出错率）rises. So one would need to set a password then.

    Apple also emphasizes that Face ID only unlocks when you stare at it. It is what Apple calls “attention aware”. So the phone won't unlock if you are just glancing at the phone for the time. It won't work either if someone puts the phone at your sleeping face or your photo.

    With beautiful canals, top art museums, and cycling culture I Amsterdam is one of the most popular travel destinations in the world. As the capital and most populous city in the Netherlands, it's often referred to as the “Venice of the North” because of its wide system of bridges and canals. Here are some key points for you to keep in mind while planning a trip there.

    Must-See Attractions

    Most visitors begin their Amsterdam adventure in the Old Centre, which is full of traditional architecture, shopping centers, and coffee shops. The top museums to visit are the Rijks museum, the Ann Frank House, and the Van Gogh Museum. As a World Heritage Site, the Canal Ring was originally built to attract wealthy home owners and an area for celebrity spotting and nightlife today.

    Transportation

    Travelers should be aware that Amsterdam Airport Schiphol is one of the busiest airports in the world. This airport is located about 15 kilometers southwest of the city center. You can catch a train from Schiphol to Amsterdam Central Station, which has many connecting routes. It's not a good idea to drive a car to the city center. Cycling is popular here, and it's easy to rent a cheap bike around the town. Amsterdam has a flat terrain (地形) and it's a good choice to explore the city on foot.

    Money-saving Tips

    Look for accommodations in Amsterdam's South District where rates are generally cheaper than in the city center.

    Buy train tickets at the machine instead of the counter to save a bit of money.

    Instead of hiring a tour guide, jump onto a canal boat. They're inexpensive and will give you a unique point of view of the city.

    Pigeons may only have a brain the size of a thimble (顶针), but it appears that pigeons can categorize and name objects in the same way human children learn new words.

    A new study from the University of Iowa has shown that the birds are capable of learning to categorize 128 different photographs into 16 basic categories.

    Scientists taught three pigeons to sort out different kinds of dogs or types of shoes, for example by using a particular symbol in exchange for a reward. When they were shown black and white pictures of previously unseen dogs or shoes, the birds were able to correctly match these with the corresponding symbols.

    The scientists behind the project say this is a similar approach taken by young children when they are first learning words for objects. However, the researchers said it took their birds around 40 days to perfect the task of learning just 16 categories.

    Professor Edward Wasserman, who led the work, said: "Our birds' rate of learning appears to have been quite slow. Would children learn faster than pigeons? Almost certainly. However, our pigeons came to the experiment with no background knowledge at all. Thus, the more relevant comparison group may be newborn babies, who indeed take 6–9 months to learn their first words."

    Writing in the journal Cognition, the researchers said their experiment was a very simple mirror of the way children are taught words — by their parents pointing to pictures and asking them to name the object.

    Pigeons are known to be smarter than many birds. Professor Bob McMurray, who also took part in the study, said the results showed that human learning is not as unique as was previously believed.

    He said: "Children are facing a huge task of learning thousands of words without a lot of background knowledge to go on. For a long time, people thought that such learning is special to humans. What this research shows is that the ways in which children solve this huge problem may be shared with many species.

    About three decades ago, China was known as the "Bicycle Kingdom". But later on, bikes were replaced by their fuel-powered competitors.

    But recent months have seen a recovery of the humble bike across China, with an increasing number of people choosing cycling instead of driving to schools, to workplaces or to do sightseeing. The introduction of bike-sharing schemes, pioneered by start-ups like Ofo and Mobike, has brought the trend to a new level.

    People can unlock the shared bikes by simply using their smartphone. The bikes are equipped with GPS and can be left anywhere in public for the next user. They're popular among many Chinese people as they provide an effective solution to the "last mile" problem, which refers to the final leg of a person's journey.

    " In places where the subway doesn't extend, where it's difficult to change from one kind of transport to another, it's so easy to get where you want to go with Mobike," Hu Hong,29,told AFP. She pedals(骑车)to her Shanghai real-estate job.

    However, the schemes have also led to problems such as illegal parking, vandalism(故意毁坏) and theft. Last month, two nurses in Beijing were placed under administrative punishment for five days for putting locks on two shared bikes. And in December, a man who stole a shared bike was sentenced to a 3-month detention(拘留),and fined 1 ,000 yuan by the Shanghai Minhang People's Court.

    " Bike-sharing is a greener method of transportation and provides a user-friendly experience,"said Liu Xiaoming, vice-minister of transport.

    " But it's a combination of online and offline business. Operators are usually strong in online services, but lack offline business experience, which causes problems."

    Now, Chinese service operators are trying to solve the problems. For example, a bike- sharing company called Mobike sets a 100-point credit score for each user, with points taken in the case of bad behavior. Once a score drops below 80, bike rental is increased to 100 yuan per 30 minutes, up from 0.5 - 1 yuan.

    It was already dark when an old man came to a small town. He found an inn and wanted to stay there for the night. After he had gone to his room, the owner said to his wife, "Look at his bag, dear. I'm sure there are lots of valuable things in it. I want to steal it when he is asleep."

    "No, no," said the woman. "He must look for his bag tomorrow morning. Then he'll take you before the judge." They thought and at last the woman had an idea. "We have forgetful grass," said the woman, "Why not put some into his food? If he has the food, he will forget to take his bag away." "How clever you are!" said the owner, "Don't forget it when you prepare supper for him."

    The old man had the food with the forgetful grass and went to bed. The next morning, when the owner got up, he found the door was open and the old man had left with his bag. He woke his wife up and said angrily, "What a fool! Your forgetful grass isn't useful at all."

    "No, no," said the woman. "I don't think so. He must forget something."

    "Oh, I've remembered!" The owner cried out suddenly, "He forgot…"

Although I learned English for years. I could not speak in complete sentences when I studied in London as an exchange student. In the beginning, I even needed to think twice before replying to a simple greeting. {#blank#}1{#/blank#}If you have a similar experience, here are some tips. 

Practice "output" more often; {#blank#}2{#/blank#} It's OK to start with only simple sentences or short paragraphs. Meanwhile, you can even practice your grammar.

At the time I didn't have opportunities to talk with the local people. So, I self-talked to describe what happened around to myself.

Another method is that you can record yourself speaking and then listen to the recordings to identify areas that needs improving. {#blank#}3{#/blank#}

{#blank#}4{#/blank#}

Language is not a hard science. It is more than just a set of rules, but a means of communication. Like small children picking up their mother tongue, we can get speaking skills more naturally by becoming completely involved in the language and using it. When using a language, we focus on the idea itself, rather than the rules.

Find the "support group" that suits you, 

Find a native tutor. A language tutor is a great idea where you can practice regularly and get your mistakes fixed in time. {#blank#}5{#/blank#} I feel much less shy when I speak English with other non-native speakers there. For example, joining a language group is really a great way to practice output.

A. Communicate with local children.

B. Raise your mind like a kid.

C. It is of much benefit to write in the language.

D. It was so painful that I was so confused about my language ability.

E. Or try some language clubs.

F. It is easier for you to "open your mouth".

G. It doesn't matter if you make mistakes.