Đề ôn thi Đề thi vào lớp 10 Trường Phổ thông Năng khiếu môn Tiếng Anh - Mã đề PTNK-46

Caves are fascinating natural formations found all over the world, but have you ever wondered how they are created? The most common type of cave is a solutional cave, formed in a specific kind of rock called limestone. The main force responsible for carving these underground wonders is simple water, but the process is anything but fast. This process can take many thousands of years, patiently shaping the world beneath our feet.

The journey begins with rain. As raindrops fall through the atmosphere, they absorb carbon dioxide from the air. This has the effect of making the water slightly acidic, creating a weak version of carbonic acid. When this acidic rainwater lands, it seeps down through the ground and into any small cracks or fissures present in the limestone bedrock. This is where the key chemical reaction begins.

Limestone is primarily made of a mineral called calcium carbonate, which reacts with acid. Over time, the limestone (21) __________ by the acidic water, creating small channels. As more water flows through these initial paths, it dissolves more and more rock. These channels grow gradually larger, eventually forming the vast rooms and passages we see in caves. It's a testament to how a gentle force can have a huge impact over a long duration.

The process doesn't stop once the main cave is formed. Inside the cave, this mineral-rich water continues to (22) __________ from the ceiling. As the water is exposed to the air inside the cave, it releases some of its dissolved carbon dioxide. This makes it less acidic and unable to hold as much of the dissolved mineral. Each drop leaves behind a tiny mineral deposit, (23) __________ builds up over centuries to form beautiful, icicle-like structures called stalactites.

The formation of caves is an incredibly slow process, requiring a precise combination of rock, water, and time. (24) __________, the results are some of the most spectacular and mysterious natural wonders on Earth. From the initial raindrop to the magnificent stone formations, the creation of a cave is a perfect example of nature's slow and persistent artistry.

Have you ever considered that a simple meal could be your passport to understanding an entire culture? This concept is at the heart of food tourism, a growing global trend where people travel specifically to experience unique culinary traditions. It’s more than just eating; it’s an immersive journey into a destination’s soul, with the local cuisine acting as a vibrant storyteller. From bustling street markets to intimate family kitchens, food offers a sensory window into the history, values, and daily life of a community, revealing layers of identity that words alone might not convey.

Food, in many ways, is a living artifact of culture. The ingredients tell tales of geography and climate, while cooking methods reflect centuries of ingenuity and adaptation. [I] A dish isn't just a collection of components; it's a narrative woven from historical influences, economic realities, and the collective memory of generations, offering profound insights into societal norms and individual identities.

Vietnam stands out globally as a prime example of a food destination where cuisine acts as a powerful cultural ambassador. [II] Its vibrant street food scene, aromatic broths, and fresh ingredients draw millions of visitors seeking authentic experiences. The iconic 2016 visit by the late chef Anthony Bourdain and President Barack Obama to a modest Bún Chả restaurant in Hanoi perfectly showcased this. [III] This simple meal, shared over plastic stools, transcended its humble origins, demonstrating how everyday Vietnamese dishes can create powerful connections and offer a genuine glimpse into the nation's heart. [IV]

For you, perhaps, Vietnamese food is simply daily nourishment—a bowl of Pho for breakfast or a Banh Mi for lunch. But understanding why tourists travel thousands of miles to savor these very dishes can give you a new sense of pride in your own heritage. Recognizing the global fascination with your local cuisine transforms it from mere sustenance into a cultural treasure. This appreciation also provides a unique way to connect with visitors, as a shared love for food often bridges language barriers and fosters mutual respect and understanding.

Ultimately, food is far more than just fuel; it is a profound cultural language. Through its flavors, aromas, and textures, it communicates stories of resilience, community, and innovation. Engaging with a culture’s cuisine, whether through cooking or simply enjoying a meal, offers an unparalleled opportunity to connect on a deeper, more personal level. It teaches us that to truly understand a place, sometimes all it takes is a single, delicious bite.