In ancient Egypt, a shopkeeper discovered that he could attract customers to his shop simply by making changes to its environment . Modern businesses have been following his lead, with more tactics（策略）.

One tactic involves where to display the goods. For example, stores place fruits and vegetables in the first section. They know that customers who buy the healthy food first will feel happy so that they will buy more junk food later in their trip. In department stores, section is generally next to the women's cosmetics(化妆品) section：while the shop assistant is going back to find the right size shoe, bored customers are likely to wander over cosmetics they might want to try later.

Besides, businesses seek to appeal to customers' senses. Stores notice that the smell of baked goods encourages shopping, they make their own bread each morning and then fan the bread smell into the store throughout the day. Music sells goods, too. Researchers in Britain found that when French music was played, sales of French wine went up.

       When it comes to the selling of houses, businesses also use highly rewarding tactics. They find that customers make decision in the first few second upon walking in the door, and turn it into a business opportunity. A California builder designed the structure of its houses smartly. When entering the house, the customer would see the Pacific Ocean through the windows, and then the poll through an open stairway leading to the lower level. The instant view of water on both levels helped sell these $10 million houses.

"Over the years the unthinkable hasbecome thinkable and today we sense we are close to being able to alter humanheredity œ#)." These were the words of David Baltimore of the CaliforniaInstitute of Technology, on December 1st, when he opened a three-day meeting inWashington to discuss the morality and use of human gene editing. Dr Baltimoreis an old hand at these sorts of discussions, for he was also a participant inthe Asilomar conference, in 1975, which brought scientists together to discussa safe way of using the then-new tcchnology of recombinant DNA, and whoserecommendations influenced a generation of biotechnology researchers.

Four decades on, the need for a similarsort of chin-wag has arisen. The InternationalSummit on Human Gene Editing has been held by the national scientific academiesof three countries — America, Britain and China. They are particularlyconcerned about whether gene editing should be used to make heritable changesto the human germ line, something Dr Baltimore described as a deep andtroubling question. Like those of Asilomar, the conclusions of this meetingwill not be binding. But the hope is that, again like Asilomar, a mixture ofcommon sense and peer pressure will create a world in which scientists aretrusted to regulate themselves, rather than having politicians and civilservants do it for them. The meeting is being held against a backdrop of rapidscientific advance, Since 2012 research into a new, easy-to-use editing tool calledCRISPR-Cas9 has blossomed. This technique involves a piece of RNA (a chemicalmessenger, which can be used to recognise a target section of DNA) and anenzyme (酶)called a nuclease that can snip unwanted genes out and paste new ones in.

Public interest was aroused in April,when Chinese scientists announced they had edited genes in non-viable ( 无活力的) humanembryos, and again in November when British researchers said they hadsuccessfully treated a one-year-old girl who had leukaemia ( 白血病),using gene-edited T-cells. T-cells are part of the immune system that attack,among other things, tumour cells. The researchers altered T-cells from ahealthy donor to encourage them to recognise and kill the patient's cancer, tomake them immune to her leukaemia drug, and to ensure they did not attack herhealthy cells.

In another recent development, a firmcalled Edit as Medicine, which is based in Cambridge, Massachusetts, has saidit hopes, in 2017, to start human clinical trials of CRISPR-Cas9 as a treatmentfor a rare genetic form of blindness known as Leber congenital amaurosis (伯氏先天性黑蒙).Though other companies are already testing gene-editing therapies, these employolder, clunkier forms of the technology that seem likely to have lesscommercial potential. Moreover, researchers at the Broad Institute, also inCambridge, said this week that they had made changes to CRISPR-Cas9 whichgreatly reduce the rate of editing errors — one of the main obstacles to thetechnique's medical use.

On the subject of germ-line editing,Eric Lander, the Broad's head, told the meeting it would be useful only in rarecases and said it might be a good idea to "exercise caution? before makingpermanent changes to the gene pool. The need for caution is advice that mightalso be heeded by those pursuing work in animals other than people, and inplants — subjects not being covered by the summit.

A. The benefits of visiting museums

B. Educational functions

C. Places for collections of objects

D. The history of museums

E. Precious chance to see famous masterpieces

F. Ways to improve their collections

    {#blank#}1{#/blank#} Museums are places where collections of objects are preserved and put on show. The objects may be anything found in nature made by man. There are museums devoted to art, science, history, industry and technology.

    {#blank#}2{#/blank#} But museums are no longer just storehouse for collections. Today nearly all museums, large or small, carry on educational programs. Museums offer guided tours, lectures, films, music recitals, art lessons, and other attractions. They organize field trips and clubs. They publish guides to help visitors to gain a better understanding of the collections.

    {#blank#}3{#/blank#} All museums share a common aim —— to attract visitors and help them to understand and enjoy the collections. Museums are always on the watch for new additions to their collections. Works of art are bought from art dealers and private collectors. Museums also accept gifts, but the large museums no longer accept everything that is offered to them. They accept only objects of collections that meet their high standards.

    {#blank#}4{#/blank#} Museums often arrange loan exhibitions of important works from private owners, art dealers and other museums. In this way a famous masterpiece may be viewed by people who otherwise might never have the chance to see it. For example, in 1963 the Metropolitan Museums of Art in New York city exhibited one of the world's most famous ladies —— Mona Lisa, painted by Leonardo Da Vinci. The government of France had lent the painting to the United States. Attendance at the Metropolitan reached an all-time high during the month Mona Lisa was shown there.

    {#blank#}5{#/blank#} What is to be gained from visiting museums? Museum exhibits can teach us about the world in which we live —— the materials it is made of, the trees and plants that cover it, and the animals that have lived on it since its beginning. We can learn about the activities of man —— his history and development as well as his accomplishments in arts and crafts. Most people see a great work of art for the first time in a museum. We cannot all be explorers or collectors in other lands. But in a museum we can see for ourselves the objects that have been gathered from every part of the world.

    With these tips you can finally get a solid night's sleep.

    Reserve Your Bed

    Get into bed just for sleeping. Avoid working, paying bills, reading, or watching television in bed. If you associate your bed only with sleep, you'll be more likely to fall asleep.

    Watch the Caffeine(咖啡因)

    Too much caffeine throughout the day can cause interrupted sleep. Limit yourself to two cups of tea, coffee, or cola, taken at least 6 hours before bedtime.

    Tap the Exercise Answer

    In a study from Stanford University School of Medicine, a group of 50- to 76-year-olds who had complained of sleep problems began proper exercise for about half an hour four times a week. Compared with a similar group of people who didn't exercise, the more active group slept an average of one hour more each night, took less time to fall asleep.

    Take a Bath

    Take a warm bath an hour or two before bed. Your body temperature will slowly drop after you get out of the tub（浴盆）, making you feel tired. Don't bathe right before bed, however, because it can briefly stimulate you enough to make it hard to fall asleep.

    Buy the Right Bed

    A bed that's too soft can cause poor sleep. Replace your mattress(床垫)if it's more than ten years old, and buy one that's as firm as you can tolerate but still comfortable.

    If 30 minutes go by and you haven't fallen asleep, don't lie in bed feeling frustrated. Get up and do something relaxing.

Special Morning Tours

    Our volunteer-led morning tours are limited to a maximum of 20 places per tour to provide a unique visiting experience. The price includes a British Museum souvenir guidebook.

    The tours begin at 09:00 and will last for 60 minutes including time at the end to take photographs. Please come to the Main entrance on Great Russell Street (WC1B 3DG) at 08:50 with your email confirmation.

    Please note that wheeled cases and large items of luggage are not allowed on British Museum premises. Cloakroom facilities are not available on these tours.

    An introduction to the British Museum

    £30 per person

    In Room 1 (Enlightenment) and Room 2 (Collecting the world) you will learn how Europeans understood the world in the 18th century, tracing the beginning of the British Museum and the development of the extraordinary collection.

    An introduction to Ancient Egypt

    £30 per person

    In the Egyptian Sculpture Gallery (Room 3) you will see impressive statues of kings and gods, monumental tomb architecture and ancient tomb reliefs (浮雕) spanning three thousand years. These include the world-famous Rosetta Stone—key to deciphering hieroglyphs(象形文字). You will learn the importance of large-scale sculpture in ancient Egyptian temples and tombs, and get the perfect introduction to this unmissable collection.

    An introduction to China and South Asia

    £30 per person

    In the Gallery of China and South Asia (Room 4), you will gain an insight into the development of Chinese civilizations, from 5000 BC to the present day. In this beautifully decorated space, you will see from blue and white porcelain (陶瓷) of the Ming dynasty to superb Buddhist and Hindu sculptures.

    Children have their own rules in playing games. They seldom need a referee (裁判) and rarely trouble to keep scores. They don't care much about who wins or loses, and it doesn't seem to worry them if the game is not finished. Yet, they like games that depend a lot on luck, so that their personal abilities cannot be directly compared. They also enjoyed games that move in stages, in which each stage, the choosing of leaders, the picking-up of sides, or the determining of which side shall start, is almost a game in itself.

    Grown-ups can hardly find children's game exciting, and they often feel puzzled at why their kids play such simple game again and again. However, it is found that a child plays games for very important reasons. He can be a good player without having to think whether he is a popular person, and he can find himself being a useful partner to someone of whom he is ordinary afraid. He becomes a leader when it comes to his turn. He can be confident, too, in particular games, that it is his place to give orders, to pretend to be dead, to throw a ball actually at someone, or to kiss someone he has caught.

    It appears to us that when children play a game they imagine a situation under their control. Everyone knows the rules, and more importantly, everyone plays according to the rules. Those rules may be childish, but they make sure that every child has a chance to win.