Đề ôn thi Đề thi vào lớp 10 Trường Phổ thông Năng khiếu môn Tiếng Anh - Mã đề PTNK-62

When we discuss distances on Earth, we use units like kilometers. However, when we look at the night sky, the distances to stars are so immense that these units become impractical. To manage these huge numbers, astronomers use a special unit of measurement. The term ‘light-year’ (21) __________ to express these cosmic distances. Despite its name, it is important to remember that a light-year is a unit of distance, not time.

A light-year is defined as the total distance that light travels in one year. The principle behind this measurement is that the speed of light is constant and the fastest possible speed in the universe. Light travels through the vacuum of space (22) __________ a phenomenal speed of approximately 300,000 kilometers per second. This consistency provides a reliable ruler for the cosmos.

Multiplying this speed by the seconds in a year results in an astonishing figure. Therefore, one light-year is equal to about 9.46 trillion kilometers. This calculation shows that even a journey of a few light-years covers a truly (23) __________ distance, one that is difficult for the human mind to comprehend fully.

This unit helps make sense of cosmic geography. For example, Proxima Centauri, the nearest star to our Sun, is about 4.2 light-years away. The Andromeda Galaxy, a neighboring galaxy which is visible on a clear night, is about 2.5 million light-years from us. This means the light we see from it today started its journey 2.5 million years ago.

In conclusion, the light-year is an essential concept in astronomy. Without it, there would be no practical way to chart the vast expanses between celestial bodies or to comprehend their scale. It simplifies cosmic calculations and gives us a way to look back in time, making it one of the most important tools for (24) __________ serious astronomer.

In today’s hyper-connected world, messaging friends is a constant part of daily life. From sharing memes to coordinating plans, digital communication forms the backbone of most interactions. However, this instant convenience brings new unwritten rules, especially concerning the "seen" receipt. [I] This simple feature profoundly alters how we perceive responsiveness, underlining the need to navigate evolving digital norms for healthy friendships.

Digital communication, or "netiquette," operates on its own unique code of conduct. Unlike face-to-face conversations with immediate cues, online interactions heavily rely on features like "read receipts" to signal engagement. [II] Globally, this function creates a peculiar social pressure. Once your message shows as "seen," an unspoken expectation often arises for a quick reply or acknowledgement. The absence of an immediate response can lead to internal questions like, "Are they ignoring me?" or "Did I say something wrong?" This subtle pressure frequently triggers unnecessary anxiety.

This phenomenon resonates strongly in Vietnam, where popular apps like Zalo and Messenger prominently display the "Đã xem" (Seen) notification. [III] For many, seeing "Đã xem" without an accompanying reply can quickly lead to misunderstandings among friends and even family. The expectation of immediate acknowledgment is high, and a delayed response might be misconstrued as disinterest or annoyance. This cultural nuance amplifies the pressure, turning a simple notification into a potential source of strained relationships if not properly understood.

As a 14-15 year old, these unwritten rules directly impact your friendships. Seeing "Đã xem" and not getting a reply can spark frustration, leading to unnecessary arguments. [IV] You might assume your friend is ignoring you, but many innocent reasons exist for a delay. Perhaps they’re busy, thinking of a thoughtful response, their phone isn’t nearby, or they’re simply taking a screen break. Understanding these varied communication styles and giving friends the benefit of the doubt is crucial for maintaining strong bonds.

So, how do you navigate this digital minefield? First, try openly communicating expectations with your closest friends; perhaps agree that "seen" doesn’t always demand an instant reply. Second, practice understanding. Just because a message is seen doesn't mean it's been processed, or that the person has time for a full response. True friendship isn't measured by reply speed, but by trust and mutual respect. By being more patient and less quick to judge, you can ensure digital communication enhances, rather than hinders, your most important relationships.