Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-31

Have you ever wondered how a simple material like sand is transformed into a clear, solid glass bottle? The journey of a glass bottle is a fascinating process that combines intense heat and precise engineering. The primary ingredient is sand, which is rich in a substance called silica. This journey begins when a mixture of sand, soda ash, and limestone is put into (35) __________ huge furnace.

Inside the furnace, the real transformation happens. The mixture is heated to an extremely high temperature. When the temperature inside (36) __________ over 1500°C, the solid ingredients melt together. They turn into a bright, glowing, thick liquid known as molten glass. This hot, liquid glass is the material from which every bottle will be formed.

(37) __________ give the molten glass a specific shape, a carefully measured amount of it is poured into a metal mold. Instantly, a blast of compressed air is blown into the mold. This forces the hot glass to expand against the mold's inner walls, taking on its shape. This automated technique is highly efficient and allows thousands of bottles (38) __________ every hour.

The bottle, still extremely hot, is not yet finished. It moves along a conveyor belt into a long oven called an annealer. In this chamber, the bottle (39) __________ gradually. A factory guide once explained to a tour group that the bottle (40) __________ very fragile if it cooled too quickly. This controlled cooling process is crucial for strength. If the cooling process were rushed, the bottle (41) __________ easily. It is also during the initial mixing stage that other chemicals can be added to create different colors, like green or brown glass.

Finally, after cooling completely, each bottle undergoes a strict quality inspection to check for cracks or other defects. Only the perfect bottles are approved, packed, and sent to companies for filling. The entire automated system, from mixing the raw materials to inspecting the finished product, runs (42) __________. It is a remarkable example of how science turns one of Earth's most common materials into an essential everyday object.

Across Vietnam, from bustling city convenience stores to quiet street-side stalls, the colorful cans of energy drinks like Red Bull and Sting are a common sight. For many students aged 14 to 15, facing long school days and extra evening classes, these drinks seem like a perfect solution. When you’re feeling exhausted before a big exam, the promise of a quick energy boost can be very tempting. But while these beverages are popular and heavily marketed to young people, it's crucial to look beyond the appealing packaging and ask a critical question: are they a helpful study aid or a significant health gamble?

The immediate feeling of alertness from an energy drink comes from its two main ingredients: caffeine and sugar. Caffeine, a powerful stimulant, works by blocking adenosine, a chemical in the brain that makes you feel tired. This creates a temporary sense of focus and wakefulness. At the same time, the high dose of sugar provides a quick rush of fuel to the body and brain. This is why energy drinks can provide them with a short-term feeling of being able to concentrate and study longer. The combination seems perfect for pushing through a difficult study session.

However, this boost is often short-lived and comes with a downside. The large amount of sugar that provides the initial energy spike is processed very quickly by the body. This leads to a “sugar crash,” a sudden drop in blood sugar levels that can leave you feeling even more tired and less focused than before. Beyond the crash, the high levels of caffeine can cause other negative effects, such as anxiety, a rapidly beating heart, and difficulty sleeping later at night. This can disrupt the very sleep patterns that are essential for memory consolidation and effective learning.

The risks are not just confined to the short term. Regular consumption of these sugary and acidic drinks can lead to serious long-term health problems. The high calorie count with little nutritional value can contribute to weight gain. Furthermore, the combination of sugar and acid can be very damaging to tooth enamel, leading to dental cavities over time. There is also the risk of developing a dependence on caffeine, where a person feels they cannot function normally without it, creating a cycle of fatigue and consumption.

In conclusion, while the immediate benefits of energy drinks are undeniable, the potential health risks, both short-term and long-term, are substantial. The temporary boost they provide often comes at a high price. For students aiming for academic success, a more sustainable approach is far better. Prioritizing a good night’s sleep, staying hydrated with water, eating balanced meals, and taking short, regular breaks from studying are much healthier and more effective strategies for maintaining energy and focus in the long run.