Mark Twain was a great writer. He was from the USA. He was born in 1835. He was also a famous speaker. He was famous for his sense of humour. Many people liked to listen to him talk because he liked to tell some interesting stories to make people laugh all the time.

    One day Mark Twain was going to a small town because of his writing. Before he was going to leave, one of his friends said to him that there were always a lot of mosquitoes in the town and told him that he'd better not go there. Mark Twain waved (摇动) his hand and said, “It doesn't matter. The mosquitoes are no relatives of mine. I don't think they will come to visit me.”

    After he arrived at the town, Mark Twain stayed in a small hotel near the station. He went into his room, but when he was just about to have a rest, quite a few mosquitoes flew about him. The waiters felt very sorry about that. “I'm very sorry, Mr Mark Twain. There are too many mosquitoes in our town.” One of them said to him.

    Mark Twain, however, made a joke, saying to the waiter, “The mosquitoes are very clever. They know my room number. They didn't come into the wrong room.” What he said made all the people present laugh heartily.

    But that night Mark Twain slept well. Do you know why? That was because all the waiters in the hotel were driving the mosquitoes away for him during the whole night.

    Have you ever pressed the pedestrian button at a crosswalk and wondered if it really worked? They're called “placebo(安慰剂）buttons” 一buttons that mechanically sound and can be pushed，but provide no functionality.

In New York City, only about 100 of the 1, 000 crosswalk buttons actually function. Crosswalk signals were generally installed before traffic jam had reached today's levels.

    But while their function was taken over by more advanced systems—such as automated lights or traffic sensors — the physical buttons were often kept, rather than being replaced at further expense. Other cities，such as Boston， Dallas and Seattle， have gone through a similar process, leaving them with their own placebo pedestrian buttons. In London, which has 6, 000 traffic signals， pressing the pedestrian button results in a reliable “Wait” light. But that doesn't necessarily mean that the “green man”— or “pedestrian stage” in traffic signal design profession — will appear any sooner.

    “We do have some crossings where the green light comes on automatically, but we still ask people to press the button because that enables accessible features,'' said Glynn Barton, director of network management at Transport for London.

    These features, such as blind tracks and hearable traffic signals, help people with visual disorder cross the road and only function when the button is pressed. As for the lights, a growing number of them are now combined and become a part of an electronic system that detects traffic and adjusts time frequency accordingly (giving priority to buses if they're running late, for example), which means that pressing the button has no effect.

    According to Langer, a Harvard psychologist, placebo buttons give us the illusion (错觉)of control — and something to do in situations where the alternative would be doing nothing. In the case of pedestrian crossings, they may even make us safer by forcing us to pay attention to our surroundings. “They serve a psychological purpose at the very least,” she added.

Are we alone in the universe? A team of scientists announced on January 6, 2015 that they had identified eight planets beyond our solar system, three or four of which orbit in their stars' "Goldilocks Zone" — the region where temperatures are not too hot or too cold for water, which is a necessary ingredient for life as we know it, to exist liquid form. This may be good news for people hoping that Earth is not the only inhabited world in the universe.

    The scientists, led by Dr. Guilermo Torres of the Harvard-Smithsonian Center for Astrophysics, made the discoveries using data collected by the planet-seeking Kepler telescope.

    NASA launched Kepler in 2009. Since then, the telescope has identified more than 1,000 planets outside of our solar system. Torres and his team analyzed the data about the eight newly discovered world to determine which ones are most likely to be similar to our Earth.

    Among the new discoveries, the scientists say the planets called Kepler438b and 442b are the closest to Earth. Kepler 438b is just about 10% larger than our planet, and gets 40% more of its energy from its star than Earth receives from the Sun. Temperatures there would be about 140 degrees. Kepler 442b is about 33% larger than Earth, but receives 30% less energy from its star. That would make it a potentially chillier world than our own. Torres says it is possible for life to exist and survive in either of those temperatures, but for that to happen, these planets would need to have another key ingredient for life: a heat-trapping atmosphere like Earth's.

    While these findings add to the possibility that life exists beyond Earth, Torres cautions against drawing conclusions, “We are not claiming they are inhabited,” he says. In fact, these planets are so far away that the scientists cannot observe them directly, which can be explanation for why for now it remains unknown whether these planets contain life. But the discovery of planets in their stars' habitable zones suggests that somewhere out there, some form of alien life may have taken hold.

    A traditional Chinese cough syrup (糖浆), called Nin Jiom Pei Pa Koa (念慈庵川贝枇杷膏), is flying off the shelves in New York stores this flu season, following a US news report.

    According to a report in The Wall Street Journal last week, Mr. Alex Schweder, a professor of design at Pratt Institute suffering a cough for about 10 days, felt better 15 minutes after he drank a bottle of Nin Jiom Pei Pa Koa. It had been recommended by his girlfriend, who first learnt about the cough syrup 30 years ago when she was living in Hong Kong.

    Mr. Schweder was shocked by the magical effects of the cough syrup, and recommended it to many people. This, together with other factors, soon made the Chinese medicine popular in New York City.

    A 300ml bottle is now sold at US$13.29 on Walmart's website. This is more than double the former price in some pharmacies (药店) in Manhattan's Chinatown, selling at about US$6 per bottle. "The number of Nin Jiom Pei Pa Koa we sold over the past few days was much more than usual," said Winnie, a sales staff member of Buy-rite pharmacy in Chinatown. "More and more Westerners are accepting this medicine because it is effective," she said.

    According to the Kingworld Medicines Group's official website, Nin Jiom Pei Pa Koa is made of "valuable Chinese herbs and honey, and has surprising effects in treating coughs." However, experts warn that taking the cough syrup can carry health risks, including when it is used with other medicines, used too much or taken instead of prescription medication (处方药).

    Dr. Keith Brenner, a specialist in pulmonary medicine at Columbia University Medical Centre New York Presbyterian Hospital, said, "I think people who use these things may not even tell the doctor about them, and it's a problem."

Every four or five years, vast quantities of warm water build up along the west coast of South America. This phenomenon, El Nino, creates storms that cause destructive floods. The result is costly.

Modern farmers come to terms with El Nino. They use money saved in good years to rebuild in bad ones. But history suggests it need not be like that. In a paper published recently, Ari Caramanica, an archaeologist at University of the Pacific, in Lima, shows how it used to be done. And the answer seems to be, "better".

Dr Caramanica and her colleagues have been studying the Pampa de Mocan, a coastal desert plain in northern Peru. Pampa de Mocan is not suitable for farming. Its soil contains little organic matter and the annual rainfall in non-Nino years is usually less than two centimeters. Today's farmers therefore depend on canals to carry water from local rivers to their fields.

It had been assumed that ancient farmers had a similar arrangement — and so they did. But Dr Caramanica also found eight canals that could carry water far beyond the range of modern farms. She thinks that they were intended to guide the floodwaters arriving during Nino years. Around a quarter of the ancient agricultural infrastructure of this area seems to have been built only for managing Nino-generated floodwaters.

Evidence from pollen supports this theory, revealing that Pampa de Mocan produced lots of crops in some years, while remaining nearly barren in others. The team also uncovered two cisterns in the area serviced by the extended canals. These, probably, were used to store extra flood-water.

These findings suggest that, rather than resisting El Nino, early farmers in Pampa de Mocan were ready to make use of it when it arrived. Modern farmers might do well to learn from them.

Grainne lived alone. My morning routine 1 with her daily walks to and from her gates, and we began having 2 there.

She was an easy conversationalists, with a good habit of focusing 3 on me as we talked. She told me she was 87, and she was surprised I was only 26. I found myself 4 her things I hadn't necessarily told anyone. "I have never felt at home anywhere, I'm traveling to find out where I 5 ." I told her.

We both looked forward to my daily 6 . However, as our friendship grew, my beloved grandfather was seriously ill. I 7 to go back to India soon.

The day before I left Dublin, I went to say goodbye to Grainne. We both knew we were likely talking to each other in person for the 8 time.

Shortly after my return to India, my grandfather 9 . I emailed Grainne telling her "I lost the only person who made me feel less 10 ." Grainne wrote back, an email full of 11 . She said: "I hope you understand you don't fit into places. You fit into 12 . You will always fit where you have people to fit with."

Although I was never able to 13 Grainne again, my friendship with her continued through emails. It was one of the most 14 friendship I've ever known. I was 26 and alone in a foreign country, and she was 87 and alone in her own home. Together we made the world 15 again.