Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-63

Have you ever heard of a river in the sky? High up in (35) __________ atmosphere, at the altitudes where commercial jets fly, there are fast-flowing, narrow currents of air known as jet streams. These are not like the gentle breezes we feel on the ground; they are powerful winds that circle the globe. These high-altitude winds are one of the most significant phenomena influencing our planet's weather patterns and even our travel.

The main jet streams are located about 9 to 16 kilometers above the Earth's surface. Their formation is complex, but they essentially exist at the boundary between cold polar air and warmer air from the tropics. A key function of the jet stream is that it (36) __________ these large cold and warm air masses. This separation is rarely a straight line; the jet stream bends and curves, creating waves in the atmosphere that can have major effects on weather below.

The position and strength of the jet stream directly influence the weather we experience. When the jet stream moves south, it can bring cold air with it, leading to colder temperatures. This makes (37) __________ its behavior crucial for accurate weather forecasting. Consequently, meteorologists use advanced tools to monitor the jet stream's path, as its shifts can signal the development of storms or periods of calm, clear weather.

For aviation, the jet stream is a very important factor. Pilots flying from west to east often try to (38) __________ of the jet stream, as this 'tailwind' can significantly reduce flight time and save fuel. If a pilot on a transatlantic flight (39) __________ the jet stream, the journey would have been much longer and more expensive. Conversely, flights going from east to west will try to avoid it to prevent a strong headwind.

In conclusion, the jet stream is a fundamental component of our planet's atmospheric system. A famous meteorologist once commented that its influence on weather (40) __________ underestimated by the public. To simply call it 'wind' doesn't (41) __________; it is a dynamic and powerful force. Understanding this 'river of air' is essential, not just for scientific curiosity, but for practical applications that (42) __________ our daily lives, from weather prediction to air travel.

In the life of a teenager, juggling school, friends, and hobbies can feel like a superpower. But what if the most potent superpower was not about doing more, but about resting effectively? For teenagers, a good night's sleep is not a luxury; it is a biological necessity. While adults need 7-8 hours, scientific evidence shows that adolescents require 9 to 10 hours of sleep per night for optimal brain function, emotional regulation, and physical health. Unfortunately, the pressures of modern life mean most teens get far less.

The science behind this need is clear. During the teenage years, the body's internal clock, or circadian rhythm, naturally shifts, making teens feel tired later at night and want to wake up later in the morning. This is not laziness; it is biology. While sleeping, the brain is hard at work. It consolidates memories from the day, strengthening the neural pathways that are essential for learning and studying for exams. This process is crucial for academic success, allowing a student to recall information more effectively. Without adequate sleep, this vital work is cut short.

In Vietnam, this challenge is particularly intense. The deep-rooted culture of 'học thêm' (extra classes) often means a student's day does not end when school does. Many attend evening classes that run late, leaving them with a difficult choice: sacrifice sleep to finish homework or sacrifice study time for rest. This dilemma creates a vicious cycle of exhaustion. Vietnamese teenagers often find themselves burning the midnight oil, and as a result, they arrive at school the next day too tired to fully absorb the lessons they studied so hard for.

The consequences of chronic sleep deprivation extend beyond poor grades. A tired teenager is often an irritable one, leading to strained relationships with family and friends. It can also weaken the immune system, making them more susceptible to illnesses. Furthermore, a lack of sleep can directly affect physical appearance, often contributing to skin problems like acne. Essentially, skimping on sleep undermines a teenager's ability to be their best self, both academically and socially.

Recognizing sleep as a superpower is the first step. The solution is not to abandon ambitions but to integrate sleep into the strategy for success. Creating a consistent sleep schedule, even on weekends, can help regulate the body's clock. Reducing screen time from phones and computers an hour before bed can also improve sleep quality. By viewing sleep as a critical component of their study routine, not an obstacle to it, teenagers can unlock their full potential and truly thrive.