PTE Listening Practice Test 7

"The Great Wall of China is often imagined as a single, continuous structure, but it is more accurately described as a network of walls, forts and watchtowers built and rebuilt by different dynasties over roughly two thousand years. Its primary purpose was defensive, intended to protect settled agricultural regions from raids by nomadic groups from the northern steppes, though it also served to control trade and the movement of people along important routes. Much of the wall visible to tourists today was built during the Ming dynasty, between the fourteenth and seventeenth centuries, using brick and stone rather than the compacted earth used in earlier sections. Contrary to a popular myth, the wall is not visible to the naked eye from the Moon, a claim that has been repeatedly debunked by astronauts, since its width is far too narrow relative to the distance involved. Watchtowers positioned at regular intervals allowed guards to send warning signals, often using smoke during the day and fire at night, that could relay a message across vast distances surprisingly quickly. Despite its scale, the wall did not always succeed in preventing invasions, and several dynasties fell to forces that breached or bypassed it entirely. Today, significant portions of the wall have deteriorated due to erosion and, in some areas, the removal of bricks by local residents, prompting large-scale conservation efforts in recent decades."

চীনের প্রাচীর একক কাঠামো নয়, বরং বিভিন্ন রাজবংশের তৈরি দেয়াল, দুর্গ ও ওয়াচটাওয়ারের একটি নেটওয়ার্ক (প্রায় ২,০০০ বছর ধরে)। এর মূল উদ্দেশ্য প্রতিরক্ষা। এটি চাঁদ থেকে দৃশ্যমান নয় — এই জনশ্রুতি ভুল। বর্তমানে ক্ষয় ও সংরক্ষণ প্রচেষ্টা চলছে।

"Gene-editing technology, particularly a method known as CRISPR, has opened new possibilities for modifying crops with far greater precision than earlier genetic modification techniques. Scientists have used CRISPR to develop crop varieties resistant to specific diseases, potentially reducing the need for chemical pesticides. The technology has also been used to create crops that tolerate drought conditions better, a development of particular interest to farmers in regions increasingly affected by irregular rainfall. Critics raise concerns about unintended ecological effects if gene-edited crops cross-breed with wild relative species, and about the concentration of this powerful technology in the hands of a small number of large agricultural companies. Regulatory approaches vary considerably by country, with some treating CRISPR-edited crops similarly to conventionally bred varieties, while others apply the same strict rules used for older genetic modification methods."

"The standardised shipping container, introduced widely in the 1950s and 1960s, is often credited with transforming global trade more than almost any single invention of the twentieth century. Before standardisation, cargo was loaded and unloaded piece by piece by dockworkers, a slow and labour-intensive process that left ships sitting idle in port for days or even weeks. Once containers of a uniform size were adopted internationally, cranes could load and unload an entire ship's cargo in a fraction of the time, dramatically reducing shipping costs and turnaround times. This efficiency made it economically viable to manufacture goods in one country and ship components or finished products cheaply to markets on the other side of the world, a key enabler of the complex global supply chains common today. Some economists argue that containerisation did more to increase global trade volumes over the following decades than any trade agreement or tariff reduction."

"Archivists responsible for preserving decades-old analogue audio and video recordings face a race against time, since magnetic tape degrades physically even when stored under ideal conditions. A common problem known as 'sticky-shed syndrome' occurs when the binding chemicals in older tape absorb moisture from the air, causing the tape to become gummy and shed its magnetic coating when played, sometimes damaging the recording permanently on a single playback. To address this, archivists sometimes carefully bake affected tapes at a low, controlled temperature for several hours, a process that can temporarily restore enough stability to allow one final, careful transfer to digital format. Because digital transfer is currently the only reliable long-term preservation strategy, and because playback equipment for many obsolete tape formats is itself becoming increasingly rare and expensive to maintain, archivists warn that a significant portion of twentieth-century audio and video history could be permanently lost within the coming decades if digitisation efforts are not accelerated."

"The Antarctic ice sheet holds roughly seventy percent of the world's fresh water, meaning that if it were to melt completely, global sea levels would rise by an estimated sixty metres."