Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-177

Quick Response (QR) codes are a (35) __________ sight in our daily lives, from posters to menus. At first glance, a QR code is a simple square filled with a black-and-white pattern. This pattern is, however, a clever system used to store a surprising amount of data, like a website link or contact details, in a compact visual format.

The structure of a QR code is a grid of small squares called modules. The arrangement of these modules represents information. In the corners, you will notice three larger squares. These are finder patterns, and they are perhaps the (36) __________ part of the code's design. They ensure the scanner can read the code correctly, so it (37) __________ be scanned from any angle.

To access the information, a smartphone is used to (38) __________ the scan. Its camera captures an image of the code. (39) __________ the entire pattern is clearly visible can the software begin its work. The software analyzes the grid, using the finder patterns for alignment, before reading every module across the square.

The next step is the (40) __________ of this visual pattern into digital data. The scanner converts the arrangement of squares into a sequence of ones and zeros, which is the binary language of computers. (41) __________ process of decoding happens almost instantly, allowing the device to interpret the data and reveal the stored information, such as opening a website.

(42) __________, a QR code is a bridge between the physical and digital worlds. A complex pattern of squares is scanned, decoded, and transformed into useful information within seconds. This process shows an efficient method of data storage that is essential in modern society.

Imagine this: you’re sitting in a popular Vietnamese coffee shop like Highlands Coffee or The Coffee House, a cold drink in your hand. You pull out your phone, and the first thing you do is connect to the free Wi-Fi. It’s a habit for millions of us, especially for teenagers wanting to save their precious mobile data while scrolling through TikTok or chatting with friends. This convenience is a major reason why these places are so popular. But have you ever stopped to think about whether this 'free' service comes with a hidden cost to your personal security?

The primary danger of public Wi-Fi lies in its lack of strong security. Most free networks in cafes, malls, or airports are 'unsecured,' meaning the data you send over them is not encrypted. This creates a perfect opportunity for cybercriminals to launch what is known as a 'Man-in-the-Middle' (MITM) attack. A hacker on the same network can use simple software to position themselves between your device and the Wi-Fi router. This allows them to intercept all the information that passes between you and the internet, essentially reading your digital mail without your knowledge.

Once a cybercriminal has access to your data stream, the potential for damage is significant. They might steal the passwords to your social media accounts, your email, or even your online banking login details. Personal conversations and private photos could also be exposed. Using this stolen information, they can impersonate you, scam your friends and family, or empty your accounts. For a teenager, losing control of a social media profile can be a particularly distressing experience, leading to public embarrassment and loss of privacy.

So, does this mean you should never use public Wi-Fi again? Not necessarily. It means you need to be smarter and more cautious. There are several effective steps you can take to protect yourself. First, avoid logging into highly sensitive accounts, such as your bank or primary email, when on a public network. Second, use a Virtual Private Network (VPN). A VPN creates a secure, encrypted 'tunnel' for your data, making it unreadable to anyone trying to spy on you. Third, always look for 'HTTPS' at the beginning of a website's address, as the 'S' stands for 'secure.' Finally, turn off your device's setting to automatically connect to available Wi-Fi networks to prevent it from joining a malicious one without your consent.

Ultimately, the convenience of free Wi-Fi doesn't have to be a threat. It simply requires a new level of digital awareness. Just as you look both ways before crossing a busy street in Hanoi or Ho Chi Minh City, you should also take a moment to secure your digital life before connecting in a cafe. By adopting these simple habits, you can enjoy your milk tea and browse the internet with peace of mind, knowing your personal information is safe from prying eyes.