Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-135

During a powerful storm, we often (35) __________ a spectacular display of light and sound. A brilliant flash of lightning illuminates the sky, followed moments later by a deep rumble of thunder. This delay has led many people to wonder about the relationship between these two powerful natural forces.

It is (36) __________ common misconception that lightning causes thunder, or that they are two separate events. In reality, lightning and thunder are two parts of the same single event: a massive electrical discharge in the atmosphere. The lightning is the flash of light, and the thunder is the sound wave created by the rapidly heated air. They are produced at the exact same moment.

The reason we see one before we hear the other is simple. This happens (37) __________ light travels much faster than sound. Light moves at an incredible speed of about 299,792 kilometers per second, reaching our eyes almost instantly. Sound, however, is significantly slower, moving through the air at only about 0.343 kilometers per second. That is why there is a noticeable gap between seeing the flash and hearing the boom.

In the past, ancient cultures created myths to explain this. One story claimed that a sky god (38) __________ his hammer to create the flash, and the sound was the echo of the strike. Today, science gives us a clearer picture. In fact, you can (39) __________ how far away a storm is. For every three seconds you count between the lightning and the thunder, the storm is approximately one kilometer away.

If sound (40) __________ as fast as light, we would see and hear the storm at the exact same moment. For many young learners, understanding this simple principle of physics makes the science of storms as (41) __________. So, next time you are safely indoors during a storm, remember (42) __________ shelter and you can try counting the seconds yourself to see science in action.

From the steaming bowls of Phở in Hanoi to the sizzling Bánh Xèo in Ho Chi Minh City, Vietnamese street food is a cornerstone of the nation's identity. This culinary world, celebrated for its authenticity and affordability, has recently gained international acclaim, with prestigious organizations like the Michelin Guide recognizing stalls in Vietnam's major cities. This recognition highlights a global appreciation for a deeply local tradition. However, for every delicious bite of 'bánh tráng nướng' shared among friends, a lingering question remains: is this beloved cultural experience a gamble with our health?

Street food is much more than just a quick meal; it is the lifeblood of urban social interaction. The plastic stools lining the pavements are not just furniture; they are front-row seats to the vibrant rhythm of city life. For teenagers, gathering at a favourite stall is a cherished ritual, a way to bond and create shared memories over affordable and tasty snacks. These food stalls are hubs of community, preserving culinary traditions passed down through generations. They represent an accessible, authentic connection to the local culture that cannot be replicated in a formal restaurant setting.

Despite its cultural importance, the other side of the street food coin presents serious health concerns. Many street food vendors operate in informal settings, often lacking access to clean water, proper refrigeration, and adequate waste disposal systems. This can lead to questionable hygiene practices. Furthermore, the origins of ingredients can be obscure, raising doubts about their quality and safety. Consequently, consumers face a potential risk of foodborne illnesses. While many vendors are responsible, the lack of consistent regulation means that they are not all held to the same high standards, leaving the public to navigate these risks on their own.

In response to these concerns, a shift is beginning to occur. Local governments have started implementing food safety training programs for vendors, and a new wave of 'clean' street food businesses is emerging, proudly advertising their hygienic practices and quality ingredients. At the same time, consumers are becoming more discerning. Armed with information from social media and online reviews, they are actively seeking out vendors known for both their delicious food and their commitment to cleanliness. This growing awareness is crucial for pushing the industry toward a safer future.

Ultimately, Vietnamese street food exists in a delicate balance. It is an irreplaceable cultural treasure that offers a unique window into the soul of the country. Navigating its world requires a mindful approach—celebrating the rich traditions while demanding higher standards of safety. The future of this culinary landscape depends on the collective effort of vendors, consumers, and authorities to preserve its authenticity while ensuring it is a safe and enjoyable experience for everyone.