C1 Reading Practice Test 4

Cut a tree trunk across and you will see a pattern most children learn to recognise: a series of concentric rings, alternately pale and dark, spreading outward from the centre. In temperate regions each ring generally represents a single year of growth, so that counting them reveals the tree's age. That much is common knowledge. What is less widely appreciated is how much more these rings can reveal, and how an entire scientific discipline, dendrochronology, has grown from them. The principle is simple. In spring and early summer, when water and sunlight are plentiful, a tree produces large, light-coloured wood; later in the year, growth slows and the new wood becomes denser and darker. A wet, mild year produces a broad ring, whereas a drought leaves a narrow one. The result is a kind of diary in which each year is recorded in the trunk, not in words but in width and density. The breakthrough that turned this curiosity into a method came early in the twentieth century, when the American astronomer A. E. Douglass noticed that trees of the same species in the same region displayed similar sequences of thick and thin rings. By matching, or "cross-dating", overlapping patterns from living trees, from old timber and from ancient beams, researchers can extend a chronology backwards far beyond the lifespan of any single tree. In some regions, such chronologies now stretch back many thousands of years, and teams working with timbers from Anatolia and the Aegean have assembled sequences that allow archaeologists to date ancient buildings with remarkable precision. The applications reach well beyond archaeology. Because a ring reflects the conditions of its year, tree-ring records are used to reconstruct past climates, including droughts and cold spells that predate any written measurements. Scientists also rely on them to check and refine radiocarbon dating, which would otherwise be less reliable. For historians of art, the technique is equally valuable: panels used for old paintings can sometimes be dated by the rings in the wood on which the work was painted. Naturally, the method has its limits. In tropical forests, where there is little difference between the seasons, trees often fail to form clear annual rings. Occasionally a tree produces two rings in a single year, or none at all, and skilled specialists must use cross-dating to detect such irregularities. Nevertheless, as a patient, low-cost source of evidence, the tree remains hard to beat. Every trunk is a record that was never intended for anyone to read, and which therefore, unlike many human documents, has no reason to flatter the past.

According to Mr Aksoy himself, cats were dirty, ungrateful and wholly unworthy of the sentimental attention that the city lavished on them. He said so frequently, usually while waiting at the ferry terminal in Kadıköy, and always in the tone of a man stating an established scientific fact. That he did so while holding a small paper bag was, as far as he was concerned, a coincidence that required no comment. I had been commuting on the same morning ferry for three years before I noticed the bag. Mr Aksoy, a retired accountant who taught evening classes in bookkeeping, occupied the same bench each day with the punctuality of a lighthouse. A grey cat with one torn ear would materialise at about ten past eight, and Mr Aksoy would glance at his watch with an expression of mild irritation, as though she were the one running behind. "Do not look at me like that," he would say to the cat. "It is not a meal. It is the leftovers of my breakfast, which would otherwise be thrown away. Practical economy, nothing more." The leftovers, I noticed, always consisted of a small piece of chicken, neatly cut, which seemed an unusual sort of breakfast for a man who professed to prefer bread and olives. One morning in November, the cat failed to appear. Mr Aksoy waited until the last whistle had sounded, then stood up with the brisk, businesslike air of someone who has been unfairly inconvenienced. He did not board the ferry. Instead, he walked slowly along the quay, peering behind crates and lifting the corner of a tarpaulin, and muttering that he had paid for a ticket and had no intention of wasting it. Twenty minutes later, a lady selling simit was happy to report that the cat had been taken to the vet by a fisherman, with, as she put it, "a small problem with her paw, nothing serious." Mr Aksoy's relief, though immediately disguised as annoyance, was visible from the other side of the terminal. "Typical," he said to nobody. "Cause a fuss, create work for everyone." He then spent the next ten minutes asking the fisherman, in great detail, about the cost of the treatment. The cat returned within the week, a little thinner and wearing a tiny shaved patch on her leg. Mr Aksoy examined her critically and pronounced the veterinary work "adequate". I do not believe he has changed his opinion about cats. He has, however, started carrying a second bag, for the days when she brings a friend.

For much of history, sleep was regarded as a kind of enforced idleness, a period of inactivity that stood between the productive hours of the day. Modern research has overturned that assumption so thoroughly that many scientists now describe sleep as one of the brain's busiest and most important working periods. Far from switching off, the sleeping brain is engaged in a series of tasks that cannot be performed as effectively, or at all, while we are awake. One of these tasks is the consolidation of memory. During the day, new information is captured in a temporary and relatively fragile form. At night, in a process researchers sometimes compare to editing a rough draft, the brain replays the day's experiences, strengthens connections that seem important and allows weaker ones to fade. Studies in which volunteers learn a set of facts or a physical skill, such as a sequence of finger movements, have repeatedly shown that people who sleep after practising perform better the next day than those who spend the same interval awake. Equally significant is the clearing of waste. While we sleep, spaces between brain cells appear to widen, allowing fluid to flush away substances that accumulate during waking hours. Although much of this research has so far been conducted on animals, and some details remain debated, it has fuelled a growing conviction that the old saying about "sleeping on a problem" contains more truth than anyone imagined. For teenagers, the implications are especially relevant. During adolescence the body clock naturally shifts, causing young people to feel alert later in the evening and to find early mornings difficult, regardless of how disciplined they are. Yet teenagers need more sleep, typically between eight and ten hours, than most adults. Where schools have moved their start times later, a number of studies have reported improvements in attendance and alertness, though results vary and it would be unwise to claim that the effect is universal. What, then, can be done in practice? The advice offered by sleep specialists is unglamorous but consistent: keep regular hours, avoid bright screens shortly before bed, and resist the temptation to study through the night before an examination. An all-night session may feel productive, but, by depriving the brain of the very process that locks new knowledge in place, it often defeats its own purpose. Rest, in other words, is not the opposite of effort; it is part of the effort itself.