Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-146

The Earth's rocks are in a constant state of change. This slow and continuous process, known as the rock cycle, describes how rocks are created, broken down, and reformed over millions of years. The (35) __________ of a rock from one type to another is driven by various geological forces. The three main types of rock—igneous, sedimentary, and metamorphic—are all connected through this incredible cycle, each one capable of turning into another.

The cycle often begins with igneous rock, which is formed from magma. This melted rock, or magma, (36) __________ rise to the surface during a volcanic eruption, where it is called lava. As the lava cools, it (37) __________ into solid rock. Granite and basalt are common examples of igneous rocks, formed from the cooling of molten material either deep within the Earth's crust or on its surface.

Over time, weathering and erosion break down all types of rock into smaller pieces called sediments. These sediments are transported by wind and water and deposited in layers. (38) __________, which is called lithification, gradually cements these layers together. Only through immense pressure (39) __________ these tiny particles become a single, solid rock. Sandstone and limestone are well-known types of sedimentary rock.

Any rock type, including igneous and sedimentary, can become a metamorphic rock if it is subjected to intense heat and pressure deep within the Earth. The original rock does not melt but instead its minerals (40) __________ a transformation, changing its structure and appearance. Metamorphic rocks are often (41) __________ than the original rocks from which they were formed. For example, limestone can be transformed into marble.

(42) __________, the rock cycle demonstrates that rocks are not static but are constantly being changed and recycled. An igneous rock can be eroded into sediment, which forms sedimentary rock, which can then be changed by pressure into metamorphic rock, and this rock might eventually melt to become magma again. The cycle has no beginning and no end, illustrating the dynamic nature of our planet.

For many teenagers, looking in the mirror and seeing a new pimple is a frustrating, yet common, part of life. Acne affects adolescents all over the world, often appearing at a time when self-esteem and confidence are still developing. In places like Vietnam, where skincare is a major topic of conversation among young people, the pressure to have perfect skin can be intense. With countless influencers on YouTube and TikTok offering advice, it’s easy to feel overwhelmed and confused about the right way to care for your skin.

To effectively manage acne, it's helpful to understand its fundamental causes. Acne is not simply about being 'unclean.' It is primarily a hormonal condition. During the teenage years, the body produces more hormones called androgens, which signal the skin's glands to produce more oil, or sebum. When this excess sebum mixes with dead skin cells, it can clog pores. This clogged pore environment is the perfect place for a type of bacteria, known as P. acnes, to grow, leading to the inflammation and redness we see as pimples.

Instead of trying complicated 10-step routines seen online, experts recommend a simple, consistent approach. A good starting point consists of three key steps: cleanse, treat, and moisturize. Use a gentle cleanser twice a day to remove excess oil without stripping the skin. For the 'treat' step, look for products containing active ingredients like salicylic acid or benzoyl peroxide. These can help unclog pores and reduce bacteria. While benzoyl peroxide can be very effective, it can also be drying, so it's crucial to follow up with the third step: moisturizing. Even oily skin needs a moisturizer to stay balanced. The key is to choose one that is 'non-comedogenic,' meaning it won’t clog your pores.

It is also important to separate fact from fiction. Many common beliefs about acne are actually myths that can make the problem worse. For example, squeezing pimples is a bad idea; it can push bacteria deeper into the skin, leading to more inflammation and even scarring. Another myth is that you must buy very expensive products to see results. In reality, consistency with affordable, well-formulated products is far more important. Finally, while a balanced diet is good for overall health, the link between specific foods like chocolate or French fries and acne is weak for most people. The focus should remain on a solid skincare routine.

Ultimately, dealing with acne is a journey that requires patience. There are no overnight cures. By understanding the causes and adopting a simple, consistent routine, you can take control of your skin's health. Remember that having pimples is a normal part of being a teenager, not a reflection of your worth.