In most languages, a greeting is usually followed by "small talk". Small talk means the little things we talk about at the start of a conversation. In English-speaking countries people often make small talk about the weather: "Nice day isn't it?" "Terrible weather, isn't it?" But there is something special about small talk. It must be about something that both people have the same opinion about. The purpose of small talk is to let both people agree on something. This makes meeting people easier and more comfortable. People usually agree about the weather, so it is a safe topic for small talk. But people often disagree about religion or politics so these are not suitable topics for small talk in English. The topics for small talk also depend on where the conversation is taking place. At football matches, people make small talk about the game they are watching, "Great game, isn't it?" At bus-stops, people may comment about the transport system, "The bus service is terrible, isn't it?"

    Greetings and small talk are an important part of conversation in any language. The way people greet each other and the things they talk about, however, may be different from one language to another. This shows that there is much more to learn when we learn a language than just the vocabulary and the grammar of the language. We also have to learn the social behavior of the people who speak it.

This year's flu season is pretty scary. To try to minimize the effects, public officials are still urging anyone who hasn't yet gotten their flu shot to get one as soon as possible. However, even if every single person got a shot in the arm, the vaccine(疫苗)— with its excellent 36 percent effectiveness—would not prevent everyone from getting infected with the annoying virus. Knowledge is power, so here's what goes on in your body when you come down with the flu.

    The influenza virus primarily attacks your nose, throat, and the tubes that lead to your lungs. But the flu is so much more than that. Your muscles ache, your head hurts, and your appetite goes down, among other things. To our surprise, almost all of these symptoms have less to do with the virus itself than with your immune(免疫的)response to them. Unfortunately, the very defense you have in place to ge rid of the flu is the reason you feel so painful when you recover.

    The virus usually enters through your mouth, typically by way of your hands. But it takes a few days for symptoms to set in. While this process might cause some harm to your nose and throat, it's nothing major, and nothing like the symptoms that typically accompany a bad or even mild case of the flu.

    The real fun starts when your immune system begins to fight. Your immune system comes in two parts: the innate system and the adaptive. The innate immune system is essentially an all-purpose tool. As soon as your body senses the presence of any injury or invader (入侵者), the innate immune system launches into action by producing tiny proteins called cytokines and chemokines. The cytokines reproduce almost immediately and start to attack the virus. This increase in immune cells creates an serious inflammation(炎症) throughout the body. But the worst is still to come. Meanwhile, the chemokines work with the adaptive immune system to help create T cells. These cells are a special type of white blood cell that works in a much more specific way: They find the influenza virus, identify what's special about it, and create something unique on their surface that finds and destroys similar invaders.

    BUS SERVICE

    New York City — Brennan, New Jersey

    (Trip time: 30 minutes each way )

    Timetable

    Buses leave the Railway Station, New York 7:00 a.m. and every half-hour thereafter(此后) until 11:30 p.m. (7 days a week).

    Buses leave Brennan Station 20 minutes before and after every hour from 6:20 a.m. to 10:40 p.m. (7 days a week ).

    Evening rush hours(5:00 p.m. to 7:00 p.m.) buses leave the Railway Station, New York every 15 minutes (Monday — Friday).

    Holidays: buses leave every hour on the hour time, each direction.

All tickets must be bought at Window 12, the Railway Station, New York, or at the Brennan Station Window before boarding buses.

    Have you ever wondered why birds sing? Maybe you thought that they were just happy. After all, you probably sing or whistle when you are happy.

    Some scientists believe that birds do sing some of the time just because they are happy. However, they sing most of the time for a very different reason. Their singing is actually a warning to other birds to stay out of their territory.

    Do you know what a "territory" is? A territory is an area that an animal, usually the male, claims（声称）as its own. Only he and his family are welcome there. No other families of the same species are welcome. Your yard and house are your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you, you might shout. Probably this would be enough to frighten him away.

    If so, you have actually scared the stranger away without having to fight him. A bird does the same thing. But he expects an outsider almost any time, especially at nesting（筑巢）season. So he is screaming all the time, whether he can see an outsider or not. This screaming is what we call a bird's song, and it is usually enough to keep an outsider away.

    Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs.

    You can see that birds have a language of their own. Most of it has to do with attracting mates and setting up territories.

    The following is a timetable in Guangzhou Baiyun International Airport.

    Rich countries are racing to dematerialise payments. They need to do more to prepare for the side-effects.

    For the past 3,000 years, when people thought of money they thought of cash. Over the past decade, however, digital payments have taken off— tapping your plastic on a terminal or swiping a smartphone has become normal. Now this revolution is about to turn cash into an endangered species in some rich economies. That will make the economy more efficient—but it also causes new problems that could hold back the transition(转型).

    Countries are removing cash at varying speeds. In Sweden the number of retail cash transaction per person has fallen by 80% in the past ten years. America is perhaps a decade behind. Outside the rich world, cash is still king. But even there its leading role is being challenged. In China digital payments rose from 4% of all payments in 2012 to 34% in 2017.

    Cash is dying out because of two forces. One is demand— younger consumers want payment systems that plug easily into their digital lives. But equally important is that suppliers such as banks and tech firms (in developed markets) and telecoms companies (in emerging ones) are developing fast, easy-to-use payment technologies from which they can pull data and pocket fees. There is a high cost to running the infrastructure behind the cash economy—ATMs, vans carrying notes, tellers who accept coins. Most financial firms are keen to abandon it, or discourage old-fashioned customers with heavy fees.

    In the main, the prospect of a cashless economy is excellent news. Cash is inefficient. When payments dematerialise, people and shops are less open to theft. It also creates a credit history, helping consumers borrow.

    Yet set against these benefits are a couple of worries. Electronic payment systems may risk technical failures, power failure and cyber-attacks. In a cashless economy the poor, the elderly and country folk may be left behind. And a digital system could let governments watch over people's shopping habits and private multinationals exploit their personal data.