Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-120

Wind is a form of solar energy that results (35) __________ the uneven heating of the atmosphere by the sun. Essentially, wind is just air in motion. This movement creates kinetic energy, which humans have used for centuries. Because the wind will always blow as long as the sun shines, it is a powerful and renewable resource. This means that we can use it to generate power without worrying about it running out, unlike fossil fuels like coal and oil.

To capture wind energy, we use special machines called wind turbines. A typical wind turbine has a very tall tower with large blades, (36) __________ look like propellers on a plane. These blades are carefully designed to capture the maximum amount of wind energy. The size and shape of the blades can vary depending on the location and the average wind speed, but they all serve the same fundamental purpose.

The process of generating electricity from wind is quite straightforward. When the wind blows, it pushes against the blades, causing them to spin. The kinetic energy from the wind (37) __________ to a central rotor. This rotor is connected through a series of gears to a generator. This rotation powers a generator to create electricity, which is then sent out to power homes and businesses. It's a (38) __________ effective process.

One of the greatest advantages of wind energy is that it is a clean fuel source. It doesn't pollute the air like power plants that rely on burning fossil fuels. (39) __________, it is a domestic source of energy, which can increase a country's energy security. Large groups of turbines, known as wind farms, are often built in windy locations like coastlines or open plains. (40) __________ turbine can generate enough electricity for hundreds of homes.

The main (41) __________ of wind energy is that it is a renewable resource that produces no greenhouse gas emissions during operation. As the world continues to seek cleaner energy solutions to combat climate change, wind power will undoubtedly (42) __________ a crucial role in our sustainable future, helping to create a healthier planet for generations to come.

At first glance, the Golden Apple Snail, or Pomacea canaliculata, seems harmless. With its shiny, yellowish-brown shell, it is often found in freshwater environments. Originally native to South America, this snail has traveled far from its home and has become one of the most significant invasive alien species in Asia. In countries like Vietnam, it is not just an interesting creature but a major threat to the nation's agriculture, particularly its vital rice fields.

The snail's journey to Asia began in the 1980s. It was intentionally introduced for aquaculture, with the hope that it could be farmed as a new food source for local populations. However, due to its ability to escape from farms and its rapid reproductive rate, the snail population exploded. A single female can lay thousands of eggs in a year, making the species incredibly prolific. This characteristic, combined with its ability to survive in diverse aquatic conditions, allowed it to spread uncontrollably through rivers, canals, and into the precious rice paddies.

The primary damage caused by the Golden Apple Snail occurs in rice paddies. The snails have a voracious appetite for young, tender rice seedlings. Farmers often find their newly planted fields devastated overnight, with the green shoots eaten down to the water level. This direct consumption of the young plants severely reduces crop yield, forcing farmers to replant their fields, which costs them time and money. They are most destructive during the first few weeks after the rice is transplanted, which is the most vulnerable stage of the plant's life.

In response to this agricultural crisis, Vietnam's Plant Protection Department and local communities have implemented various control strategies. One common method is manual collection, where farmers physically remove the snails and their bright pink egg clusters from the fields. Another approach involves using biological controls, such as introducing ducks into the paddies to eat the snails. While chemical pesticides are also used, they pose risks to the environment and human health, so their use must be carefully managed. The goal is to manage the snail population, as complete eradication is extremely difficult.

The story of the Golden Apple Snail in Vietnam is a powerful lesson. It demonstrates how a single, seemingly small change—the introduction of a non-native species—can cascade into enormous environmental and economic problems. It highlights the delicate balance of ecosystems and serves as a critical reminder of the need for caution and thorough research before introducing any alien species into a new environment. The fight against this unwanted guest continues, underscoring the ongoing challenge of protecting local biodiversity and food security.