Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-111

The Global Positioning System, or GPS, is a remarkable technology that many of us use every day without a second thought. It is a satellite-based navigation system that provides location and time information anywhere on or near the Earth. This system is made up of a network of satellites orbiting our planet and the GPS receivers in our devices, like smartphones or car navigation units. Its primary function is to help a receiver determine its exact position.

The first part of the system is the satellite network. There are more than twenty-four GPS satellites orbiting the Earth at a very high altitude. Signals (35) __________ constantly from these satellites down to the surface. Each signal travels at the speed of light and contains information about the satellite's position and the exact time the signal was transmitted. This timekeeping is incredibly accurate, thanks to the atomic clocks on board each satellite.

The second part is your GPS receiver. The receiver's main job is to listen for these signals. It needs to pick up signals from multiple satellites to work properly. The receiver, (36) __________ is often built into your phone, detects these signals and uses the information within them. The data contains (37) __________ timing information that is crucial for the next step of the process. It is a passive device, meaning it only receives signals and does not send them.

The calculation of your location is based on a principle called trilateration. To calculate a 2D position, which includes latitude and longitude, signals from at least (38) __________ satellites are needed. The receiver measures the time it takes for a signal to travel (39) __________ a satellite to the device. (40) __________, for a more accurate 3D position that includes altitude, a fourth satellite is required. This information helps to calculate the (41) __________ to each satellite, which is a key part of finding your location.

Once the receiver has the distances from four or more satellites, it can calculate its exact position in a fraction of a second. This location is then shown on your device's map application. The entire process is continuous, allowing for real-time tracking of your movement. (42) __________ person with a modern smartphone can benefit from this amazing technology, whether for finding a new restaurant or navigating through an unfamiliar city.

When you think about where to hang out with your friends on a weekend, a local park might come to mind. For many teenagers, these green areas are simply places for socializing and relaxation. However, their role in a city is far more significant. In densely populated urban centers, from New York to Ho Chi Minh City, planners and citizens are increasingly recognizing that parks, gardens, and other green spaces are the 'green lungs' of a city, essential for its health and survival.

The most direct benefit of these green lungs is environmental. Trees and plants are masters at improving air quality. They absorb carbon dioxide and other harmful pollutants from traffic and industry, and in return, release the oxygen we need to breathe. Furthermore, parks play a crucial role in fighting the 'urban heat island' effect, where cities are significantly warmer than surrounding rural areas. The shade from trees and the evaporation from plants cool the air, providing a much-needed escape from the summer heat. They also offer a vital habitat for biodiversity, supporting various species of birds, insects, and small animals that would otherwise struggle to survive in a concrete jungle.

Beyond the environment, green spaces have a profound impact on human well-being. Numerous studies have shown that spending time in nature can significantly reduce stress, anxiety, and depression. A simple walk in a park can improve your mood and mental clarity. These areas also encourage physical activity. Whether it's jogging on a path, playing football on a field, or doing yoga on the grass, parks provide free and accessible opportunities for people of all ages to exercise, contributing to better physical health and preventing lifestyle-related diseases.

Finally, parks are powerful engines for social and economic vitality. They act as community hubs, bringing people from diverse backgrounds together and fostering a sense of local identity and connection. This is especially true in large-scale developments, such as Vinhomes Central Park in Ho Chi Minh City, which was designed around its massive green space. These major urban developments often highlight their large parks as a primary attraction. They understand that a beautiful green space increases property value and appeals to families and individuals seeking a higher quality of life. This proves that investing in parks is not just an expense but a smart investment in the city's future.

In conclusion, urban parks are much more than just pretty patches of green. They are hard-working, multi-functional systems that clean our air, cool our cities, improve our health, and strengthen our communities. As our cities continue to grow, protecting and creating these green lungs is not a luxury, but a fundamental necessity for building sustainable and livable urban environments for everyone.