Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-163

When you look at skyscrapers or long bridges, you might wonder how they can be so strong. A key component behind their stability is the I-beam. While the overall design of a structure is complex, the choice of (35) __________ is also critical. The I-beam is a fantastic example of smart engineering, providing incredible strength without being excessively heavy. This clever shape allows the beam (36) __________ immense weight, making it essential for modern construction.

The I-beam gets its name from its cross-section, which looks like the capital letter 'I'. An I-beam is (37) __________ two horizontal plates, known as flanges, which are at the top and bottom. These are connected by a thinner, vertical plate called the web. This specific arrangement is not accidental; it is a highly calculated design that maximizes the beam's performance under stress.

The secret to the I-beam's strength lies in how its parts work together. The flanges are far apart, which is important (38) __________ this placement helps resist bending forces effectively. The top flange resists compression, while the bottom flange resists tension. The web connects these two parts and resists shear forces. By concentrating material in the flanges, engineers are creating (39) __________ incredibly efficient and strong structural element.

The efficiency of the I-beam becomes clear when compared to a solid rectangular beam. If a solid rectangular beam of the same height were used, it (40) __________ significantly more material, making it heavier and more expensive. The I-beam uses material only where it is most needed, removing the less critical mass from the center. This is a perfect example of how the 'less is more' principle (41) __________ in engineering.

Due to its shape, an I-beam, usually made of steel, provides a superior strength-to-weight ratio. An experienced architect once said that he (42) __________ I-beams in almost all of his skyscraper designs because they were so reliable and cost-effective. Ultimately, the I-beam is a fundamental building block that combines simple geometry with core engineering principles to build the world around us.

In 2021, the art world was stunned when a digital artwork, a single JPG file, sold for $69 million. For many, this was confusing. How can a file that anyone can copy and view for free be so valuable? The answer lies in a revolutionary technology called NFTs, or Non-Fungible Tokens. An NFT is not the artwork itself, but a unique digital certificate, stored on a secure public ledger called a blockchain, that proves who owns the 'original' version of a digital creation. This technology is transforming our understanding of ownership in the digital age.

The core idea behind an NFT's value is its ability to create provable digital scarcity. While you can screenshot a digital painting, only one person can own the NFT linked to it. The blockchain acts as a global, unchangeable record of this ownership. Think of it like a famous artist's signature on a limited-edition print; it verifies authenticity and distinguishes the original from a mere copy. This verification process is what allows a digital file, which is inherently easy to duplicate, to be treated as a unique and valuable asset, much like a physical painting.

This new technology has opened up exciting opportunities for artists worldwide. Traditionally, digital artists struggled to sell their work as unique pieces. Now, through NFTs, they can sell directly to a global audience, bypassing the need for physical galleries and agents. This is particularly true in Vietnam, where a vibrant community of digital artists is emerging. Organizations like the Vietnam NFT Union help local creators navigate this new market, providing them with a platform for global recognition and a new source of income that was previously inaccessible.

However, the world of NFTs is not without its controversies and risks. A major criticism is the significant environmental impact, as the blockchain technology that powers NFTs consumes a large amount of energy. Furthermore, the market is highly volatile, meaning the value of an NFT can increase dramatically but can also crash, leading to huge financial losses for investors. The digital nature of the space also makes it a target for scams and theft, and buyers must be extremely cautious.

Ultimately, NFTs represent a major shift in how we perceive and trade art. They challenge our traditional concepts of value, which were often tied to physical objects. While the technology is still young and faces legitimate criticisms, it has provided a powerful new tool for digital creators and is forcing a global conversation about what it truly means to own something in our increasingly digital-first world.