Đề ôn thi Đề thi vào lớp 10 Trường Phổ thông Năng khiếu môn Tiếng Anh - Mã đề PTNK-02

The human heart is an incredible muscle, working tirelessly every second of every day. Its main purpose is to pump blood throughout the body, delivering essential oxygen and nutrients to every cell. This process, known as circulation, is driven by a powerful, four-chambered pump. Understanding how this system works reveals a marvel of natural engineering. The heart is a vital organ, and its constant, rhythmic beating is the soundtrack to life itself. Without its nonstop work, our bodies could not function.

First, deoxygenated blood, which is low in oxygen after traveling around the body, enters the heart's right atrium. From there, it is guided through a one-way door, called a valve, into the right ventricle. The role of valves is critical; after blood passes through, the valve (21) __________ close completely to prevent any of it from flowing backward. This ensures that blood moves in a single, forward direction through the heart's complex pathways.

Next, the muscular right ventricle contracts, powerfully pushing the deoxygenated blood out of the heart and into the pulmonary artery, which leads directly to the lungs. In the lungs, a vital exchange takes place. The blood releases its waste product, carbon dioxide, and picks up fresh oxygen. Now rich with oxygen, this bright red blood travels back to the heart, this time entering the left atrium through the pulmonary veins.

The oxygenated blood then moves from the left atrium into the left ventricle, the heart’s most powerful chamber. With a forceful squeeze, the left ventricle pumps this blood into the aorta, the body's largest artery. The aorta then branches into a network of smaller arteries, delivering the oxygen-rich blood to all tissues and organs, from the brain to the toes, thus completing the (22) __________. (23) __________ does this cycle stop; it continues with every single heartbeat.

The heart pumps, the lungs oxygenate, and the blood vessels transport. This is a continuous loop that ensures every part of the body is nourished and cleansed. (24) __________, the heart's four-chamber system, with its specialized valves and powerful ventricles, is an incredibly efficient machine, perfectly designed to sustain life through its rhythmic, unending work.

When we pack our bags for an adventure to another country, we often focus on the sights, tastes, and memories. However, equally important is understanding and practicing travel etiquette – the unwritten rules of polite, respectful behavior in a different culture. It’s more than just avoiding offense; it’s about ensuring smooth interactions, fostering mutual respect, and truly appreciating new places. [I] In essence, every traveler becomes an unofficial ambassador for their home country, representing their nation through their actions and demeanor abroad.

Travel etiquette encompasses a wide range of considerations. How we dress significantly impacts local perceptions, particularly at religious or conservative sites where modest attire is expected. Tipping customs vary wildly; what's standard in one place might be an insult or non-existent elsewhere. Simple greetings, gestures, and even eye contact carry different meanings across cultures. Respect at cultural and historical sites—not touching artifacts, speaking quietly, following local customs—ensures their preservation for future generations. [II] Mindfulness of these details enriches our experience and shows genuine appreciation for our hosts.

Vietnam deeply understands responsible tourism. Through campaigns like "Go Vietnam!", the Vietnam National Authority of Tourism showcases our nation's beauty while actively promoting a visitor code of conduct. This initiative encourages respectful behavior, environmental conservation, and positive community engagement from those visiting our shores. This national effort highlights that being a good guest is a two-way street: just as we expect visitors to Vietnam to respect our traditions and land, we too should extend the same courtesy when we are guests in foreign lands. It contributes to a global culture of respectful interaction.

For young people, especially 14-15-year-olds, travel etiquette is incredibly relevant. As you explore the world—on family vacations, school trips, or future independent adventures—you carry your country's identity. Every interaction and action reflects not just on you, but on Vietnam. Knowing how to greet people appropriately, dress respectfully, or understand local customs ensures positive, memorable experiences, avoids misunderstandings, and leaves a good impression of yourself and your homeland. [III] It empowers you to be a confident, considerate global citizen, fostering cross-cultural understanding.

Ultimately, being a good guest in someone else's country is about empathy, awareness, and a willingness to learn. It’s about embracing differences, rather than expecting others to conform to our norms. [IV] It builds bridges of understanding, encourages appreciation for diverse cultures, and makes us better, more appreciative individuals, leaving goodwill wherever we go.