Đề ôn thi Đề thi vào lớp 10 Trường Phổ thông Năng khiếu môn Tiếng Anh - Mã đề PTNK-166

Have you ever wondered how you can run, jump, or even just smile? All these actions are possible thanks to our muscular system. This complex network allows us to perform a huge variety of movements, from lifting heavy objects to blinking our eyes. These are our voluntary muscles, which we control consciously. Our brain sends signals along nerves, telling these muscles when to act.

Each muscle is made of thousands of tiny strands called muscle fibers. When a muscle receives a signal from the brain, its fibers shorten, or contract. This contraction creates a pulling force. It’s important to remember that muscles can only pull; they cannot push. To create movement, they must work with bones and joints, pulling on them to move parts of the body. This is (21) __________ fundamental principle of biomechanics.

Because muscles can only pull, they must work in pairs to create movement in opposite directions. (22) __________, when you bend your arm, your bicep muscle contracts and pulls your lower arm up. At the same time, its partner muscle, the triceps, relaxes. To straighten your arm, the opposite happens. The triceps contracts and the bicep relaxes. They need to work with each other to allow for smooth motion.

Besides voluntary muscles, we also have involuntary muscles that work automatically. Your heart, for instance, is a powerful muscle that works without you thinking about it. It has to keep pumping blood to all parts of your body, so it truly has to work around the clock. Our body depends on these muscles to continue functioning even when we are asleep.

A fitness expert once explained that a client asked him how he (23) __________ so strong. He told them it was all about understanding these muscle pairs. If we did not have muscles working together in pairs, every movement (24) __________ much more difficult and less controlled. This clever system of contracting and relaxing partners is what gives us the ability to perform everything from simple gestures to complex athletic feats.

Earth is slowly but surely becoming not enough for the adventurous traveler. What once seemed like science fiction is rapidly transforming into a tangible reality: space tourism. Visionary private companies, such as Elon Musk's SpaceX and Jeff Bezos' Blue Origin, are at the forefront of this groundbreaking industry. They are developing vehicles capable of carrying civilian passengers beyond Earth's atmosphere, offering unprecedented opportunities for those with the financial means. While still nascent, the idea of a vacation beyond our planet is no longer just a dream for a select few.

Currently, space tourism primarily involves suborbital flights, where passengers experience minutes of weightlessness and witness Earth's curvature before returning home. [I] These brief excursions offer an unparalleled perspective and profound awe. [II] A single ticket can cost millions of dollars, highlighting its exclusivity. [III] Despite prohibitive costs, demand from pioneering space enthusiasts is strong, signaling a future where technology advances and costs potentially decrease. [IV]

While direct space travel remains distant, Vietnam's youth are increasingly captivated by the cosmos. The nation's strong emphasis on STEM education naturally fosters curiosity about aerospace. Initiatives like Vingroup's VinSpace Astronomy Club actively engage students, igniting passion for space exploration through hands-on learning and observation. These programs cultivate a generation that understands rocketry and orbital mechanics, preparing them for a future where space might be more accessible, even if just through technological contribution.

For 14-15-year-olds, space tourism isn't just about lunar vacations. The technologies developed for safer, more efficient space travel have broad implications. Innovations in propulsion, materials, and life support, driven by space tourism, can advance fields from aviation to renewable energy. This is about pushing human ingenuity's boundaries. Representing the "final frontier," its rapid development means significant space milestones will unfold within your lifetime, shaping the future in unexpected ways.

Ultimately, whether a short hop to space or a future lunar resort, space tourism signifies a profound shift in humanity's relationship with the cosmos. It challenges our perception of boundaries and possibilities. While still a luxury, its existence testifies to human ambition and the relentless pursuit of discovery. It’s a clear signal that for some, Earth is not enough, and the vast expanse of space beckons, promising new adventures and unforeseen breakthroughs benefiting everyone.