IELTS Academic Reading Practice Test 485

On the edge of the Gobi Desert, about twenty-five kilometres from the town of Dunhuang in north-western China, a line of caves is cut into a cliff above a river valley. There are hundreds of them, some barely larger than a cupboard and others the height of a cathedral. For more than a thousand years merchants, monks and officials stopped here, where the Silk Road divided to pass either side of the Taklamakan Desert, and commissioned shrines in the soft rock. The result, known as the Mogao Caves or the Caves of the Thousand Buddhas, is the largest group of Buddhist cave temples anywhere in the world.

Tradition holds that the first cave was dug in 366 CE, after a wandering monk named Yuezun saw a vision of a thousand figures bathed in golden light on the cliff face. Whatever the truth of that story, the site grew steadily for the best part of a millennium. The earliest caves date from the fourth and fifth centuries; the latest were decorated under the Yuan dynasty in the fourteenth. Patrons included emperors and local governors, but also merchants and ordinary families who clubbed together to pay for a small shrine, and monks who had travelled from as far away as India and Central Asia.

Almost every cave is covered, from floor to ceiling, with painting. The pigments were made from ground minerals — azurite for blue, malachite for green, cinnabar for red — mixed with animal glue, which is why some of the colours remain startlingly vivid after a thousand years of dry desert air. The statues were modelled in clay over wooden frames and then brightly painted. Some caves contain hundreds of small figures arranged in rows along the walls; others are dominated by a single seated Buddha. The largest of these, in Cave 96, is more than thirty-five metres high and is enclosed by a wooden structure of nine storeys that has become the emblem of the site.

The cave that made the site famous was found by accident. In 1900 Wang Yuanlu, a Daoist priest who had appointed himself caretaker of the neglected temples, was clearing sand from a corridor when he noticed a crack in the plaster. Behind it lay a small chamber, roughly three metres square, packed to the ceiling with bundles of paper. The room, now known as the Library Cave or Cave 17, had been sealed for about nine hundred years. Wang could not read the documents, and the local officials to whom he eventually reported the find showed little interest.

What the chamber contained was extraordinary: an estimated fifty thousand manuscripts and fragments, together with silk paintings, textiles and printed sheets. They date mainly from the fifth to the eleventh centuries. Most are Buddhist texts, but there are also contracts, letters, medical recipes, school exercises, tax records and calendars, written in Chinese and in Tibetan, Uyghur, Sogdian, Khotanese and Sanskrit. Together they offer an unbroken picture of daily life on a trade route. Among them is a copy of the Diamond Sutra bearing a printed date of 868 CE, which makes it the earliest dated printed book known to survive.

Why the chamber was closed is still debated. One suggestion is that it served as a store of sacred waste — worn-out manuscripts that could not simply be thrown away. Another is that the documents were hidden for safety when the Tangut state of Xi Xia threatened the region in the eleventh century; the fact that they were never retrieved would then suggest that their owners did not return. Neither explanation is entirely convincing, and the question remains open.

News of the find eventually reached foreign scholars, and their arrival changed everything. In 1907 the Hungarian-born British archaeologist Aurel Stein spent several days at the site and left with more than twenty cases of manuscripts and paintings, in exchange for a payment towards the repair of the caves. The French sinologist Paul Pelliot followed in 1908 and, having examined the collection in detail, sent a large selection to Paris. Japanese and Russian expeditions collected further material, so that the documents were scattered among institutions in London, Paris, St Petersburg and Tokyo. In 1910 the Chinese government ordered what remained to be moved to Beijing.

The dispersal is a painful subject in China, where Wang Yuanlu has often been condemned as a fool and Stein as a thief. Yet it also created a new field of research. Scholars in several countries began to compare texts held in different collections, and the work of dating, translating and interpreting them now goes by the name of Dunhuang studies, drawing on archaeology, philology and social history at once.

Serious conservation began only in 1944, when the Dunhuang Academy was founded under the painter Chang Shuhong. Since then the Academy has stabilised crumbling plaster, planted windbreaks to hold back the desert, and imposed a limit on the number of visitors admitted each day, because moisture in human breath damages pigment. Detailed digital images of the most important caves are now being recorded and published online, so that the paintings can be studied without being visited. UNESCO inscribed the Mogao Caves on the World Heritage List in 1987.

Anyone who has waited at a supermarket checkout has taken part in an experiment in resource allocation. A queue forms whenever more people want a service at a particular moment than there are staff or machines to provide it. The usual rule is first come, first served, which has the great merit of being easy to understand and hard to challenge: nobody can claim that the person at the front has bought an advantage. A queue therefore allocates time rather than money, and it does so in public, since the order of service is visible to everyone behind and in front. The alternative, allowing prices to rise until demand falls, may be efficient in theory but is politically unacceptable when the service is a hospital or a passport office.

The scientific study of waiting began not in shops but in telephone exchanges. In the first decade of the twentieth century a Danish engineer, Agner Krarup Erlang, was employed by the Copenhagen telephone company, where he was troubled by a practical question: how many lines and operators were needed if callers were not to be left listening to silence? Erlang treated arriving calls as a stream of random events and worked out formulas for the probability that a caller would have to wait. His methods, and the unit of traffic intensity named after him, are still used to decide how many staff a call centre needs at each hour of the day.

A later result, proved by John Little in 1961, is simpler and applies to almost any queue. It states that the average number of customers in a system equals the rate at which they arrive multiplied by the average time each of them spends there. The practical consequence is that a manager who wants a shorter line has only two options: reduce the arrival rate, by means of appointments or by spreading demand over time, or reduce the time each customer spends being served. Extra staff work on the second; the equation offers no third lever.

Which lever matters most depends on how arrivals vary. When customers join separate queues at neighbouring counters, the total wait can be surprisingly long, because one slow customer at one till blocks everyone behind them while the other tills stand idle. Pooling demand into a single line that feeds several counters removes this problem, and such a line also moves, on average, faster. Banks, airports and some supermarkets have adopted it for exactly that reason. It has a psychological advantage too: customers can see that the person ahead of them in the one line arrived first, so the arrangement feels fair.

Not every queue, however, works on a first-come basis. Where the cost of waiting is unequal, a priority system may be thought justified: hospital emergency departments treat the most seriously ill first, whatever order patients arrived in, and airports sell fast-track access to security. Lanes of this kind are now familiar in Europe and North America. Economists tend to approve, since a queue that ignores urgency wastes the time of those who can least afford it. Others object that paid priority turns waiting from a burden shared by all into one more thing that money can remove.

Alongside the mathematics there is a psychology of waiting, summarised in an influential essay by David Maister, a former professor at Harvard Business School. Maister argued that the length of a wait, as measured by a clock, matters less than how it is experienced. Occupied time passes faster than unoccupied time, which is why airports install moving walkways and theme parks fill their queues with screens. People dislike a wait that has not been explained, and a wait of unknown length feels longer than a longer wait with a known end. Above all, waiting feels worse when it appears unfair — when someone who arrived later is served first, or when a second till opens and those at the back of the line rush to it.

Some organisations have responded by moving the wait out of sight. Call centres offer to ring customers back rather than keep them listening to music, and theme parks sell timed tickets that allow visitors to join a short queue later instead of a long one now. Supermarkets have experimented with handheld scanners that let shoppers pack their bags as they walk the aisles, shifting the work of the till into the shop itself. The waiting has not disappeared; it has been redistributed, sometimes onto people who did not choose it.

What the models cannot yet capture is the behaviour of a queue as a social system. Equations assume that arrivals are random and that service times follow a known pattern, yet customers react to one another: they abandon a line that looks too long, they join what seems the shortest and then regret it, and they enforce informal rules about queue-jumping with surprising force. Field studies suggest that ideas of fairness differ between countries and between types of queue, but the evidence is patchy, and it is not clear how far laboratory findings carry over to a crowded platform on a wet Monday. For the moment, the most reliable advice is also the oldest: tell people what is happening, and make sure the line is seen to move.

Few public institutions are financed in so odd a way as public broadcasting. In Britain a household that watches or records live television, or uses the national broadcaster's online service, must pay a flat annual sum, and the money goes to a corporation expected to be independent of both the government and the market. In Japan, similarly, households with equipment able to receive the national service are required to contribute. For decades the arrangement went largely unexamined. Now that viewing has moved online, the question of whether such a fee can be justified has become urgent, and it divides people who agree about the value of public broadcasting.

Campaigners for public service broadcasting begin with market failure. Programmes for small audiences — regional news, specialist music, religious broadcasting, drama in minority languages — are expensive and unattractive to advertisers, and a commercial system will make few of them. Public money, the argument runs, buys what a market will not supply.

Such programming is also, its supporters say, a form of national infrastructure, in the way that museums and libraries are. The second claim concerns independence. A broadcaster that need not sell advertising, and does not depend on an annual grant voted by politicians, is harder to intimidate: it can report critically on its own government and on the companies that would otherwise be its sponsors.

Critics attack the mechanism rather than the principle. Consumer organisations point out that a flat charge is regressive: the same sum is a minor inconvenience to a wealthy household and a real burden to a poor one, and it is demanded from people who may never watch the service at all. Nor is the charge easy to avoid, since it is backed by inspection and, in some countries, by prosecution. Media economists who favour market solutions go further, contending that a guaranteed income makes an organisation slow and self-satisfied, and that the money would be better left with consumers, who are, in their view, the best judges of what should be made.

Commercial broadcasters make a different complaint. They must earn their income by attracting audiences, whereas a publicly funded rival can schedule programmes that few people watch and still receive its money. Competition, they argue, is distorted: the public broadcaster bids for the same talent and the same sporting rights with funds that no advertiser had to approve. Defenders reply that the public broadcaster's remit is precisely to do what the market will not, and that the two kinds of organisation are not, or should not be, chasing the same audience.

Much therefore turns on governance. In Britain the size of the licence fee is settled periodically by the government of the day, an arrangement that gives ministers leverage over an institution they are supposed to keep at arm's length. Committees of regulators and parliamentary bodies have repeatedly recommended that decisions about the level of the fee be removed from immediate political control, for example by handing them to an independent panel working to a fixed formula. The details matter less than the principle: the further the money is from the cabinet table, the more credible the broadcaster's claim to independence.

The technological case against the fee is the most recent. When the charge was devised, a television set was a large object in a living room, and detecting one was a matter of equipment and observation. Viewing now happens on laptops, phones and tablets, often through services that have nothing to do with broadcast schedules. Enforcement becomes both harder and, to many people, more intrusive. Several countries have already replaced the licence fee with a charge collected through the tax system, which is cheaper to administer but makes the broadcaster's income depend, in the end, on the state.

Audience research in several countries indicates that younger viewers make far less use of public broadcasting than their parents do. This is a serious difficulty for the universal model, because a service used mainly by older and better-off households begins to look less like a public good and more like a club whose members happen to be charged a membership fee. Defenders respond that the remedy is to reach new audiences online rather than to abandon universality, and that a service which tries to please everyone is bound to be used unevenly.

My own view is that the licence fee is the least bad method yet devised, but that it cannot survive much longer in its present form. The principle — that some broadcasting should be paid for by everyone and accountable to the public as a whole rather than to advertisers or ministers — remains sound. The device of charging households for possessing a particular kind of equipment does not. The obvious alternative is a hypothecated levy on all households, or a small share of general taxation ring-fenced for public broadcasting.

Such a change would not solve every problem. A levy collected by the state makes political interference easier, not harder, and the amount would still have to be decided by someone. It would, however, remove the regressive element at a stroke if it were graduated by income, end the need for enforcement visits, and detach public broadcasting from a technology that is quietly disappearing. The argument is too often conducted as though the only choices were the present system and a subscription. In fact the question is narrower and more practical: who should pay, and how should the sum be fixed?