The world’s largest iceberg, known as A23a, entered the final stage of breaking apart after a life that lasted nearly forty years. According to the China Meteorological Administration, the iceberg recently broke apart for the last time. The largest remaining piece was only 11 kilometers long and covered just 35.2 square kilometers. As this was far below the official size requirement for tracking icebergs, scientists have stopped monitoring A23a as an independent object, marking the end of its long journey.

A23a first broke away from the Filchner Ice Shelf in Antarctica back in 1986. At that time, it was enormous — about 4,170 square kilometers in area and nearly 400 meters thick. Its total weight was estimated at around one trillion tons. For many years, the iceberg remained stuck on the sea floor in the Weddell Sea and barely moved. It was not until around 2020 that melting ice allowed it to lift slightly, though real movement only began in late 2022.

From early 2023 onward, A23a began to drift more quickly. It was recorded by Guinness World Records as the largest iceberg on Earth at that time, with an area of 4,035 square kilometers. It then left the Weddell Sea in 2024 and entered the powerful Antarctic Circumpolar Current. Throughout 2025, the iceberg suffered multiple major breakups, shrinking from 3,536 square kilometers at the start of the year to roughly 1,400 square kilometers. Another major collapse in January 2026 further reduced its main body to just 503 square kilometers.

1.1. Why did scientists stop tracking A23a as an independent iceberg?

A It melted away completely.

B It dropped below standard.

C It drifted out of range.

D It split into two parts.

解析：选B。B 细节理解题。第一段最后两句明确指出“The largest remaining piece was only 11 kilometers long and covered just 35.2 square kilometers. As this was far below the official size requirement for tracking icebergs, scientists have stopped monitoring A23a as an independent object.” 即剩余面积远低于官方追踪冰山的大小标准，因此科学家停止将其作为独立对象监控。选项B “It dropped below standard”（低于标准）与此直接对应。A项错误，因为原文只提到冰山破碎，并未完全融化消失；C项错误，文中并未提及冰山漂移超出监测范围；D项错误，冰山虽然多次分裂，但分裂本身并不是停止监测的理由。故选B。

2.2. What kept A23a almost unmoving for decades after 1986?

A Its enormous thickness.

B Lack of ocean currents.

C Freezing temperatures.

D Being stuck on the seabed.

解析：选D。D 推理判断题。依据原文“For many years, the iceberg remained stuck on the sea floor in the Weddell Sea and barely moved”，A23a在脱落之后的数十年里一直搁浅在海床上，因此无法自由漂移。A项错误，厚度大只是冰山能够搁浅的条件，并非阻碍移动的直接原因；B项错误，文中并未提到缺少洋流，且冰山后来也进入了强劲的洋流中；C项错误，原文没有将低温作为其长期静止的原因。故选D。

3.3. What can we learn about A23a in 2025?

A It joined a powerful current.

B It lost most of its volume.

C Its thickness was reduced.

D Its record area was confirmed.

解析：选B。B 细节理解题。原文提到“Throughout 2025, the iceberg suffered multiple major breakups, shrinking from 3,536 square kilometers at the start of the year to roughly 1,400 square kilometers”，2025年这座冰山多次崩解，面积大幅缩减，失去了大部分体量。A项错误，进入南极绕极流是2024年发生的事，并非2025年；C项错误，文中只提及面积变化，没有提到厚度变化；D项错误，吉尼斯世界纪录是在2023年认证的，与2025年无关。故选B。

4.4. What is the function of mentioning Fengyun weather satellites?

A To highlight China’s advanced technology.

B To detail the final drifting path.

C To support the breakup process with evidence.

D To predict future iceberg movements.

解析：选C。C 推理判断题。最后一段开头说“China’s Fengyun weather satellites carefully recorded the iceberg’s final months.” 随后详细记录了2月底到4月初的崩解过程和面积变化数据。这些具体数据来自风云卫星的观测，旨在为A23a最后崩解过程提供客观的证据支撑。因此选项C “To support the breakup process with evidence”（为崩解过程提供证据支持）最为准确。A项错误，文章的写作目的是介绍冰山演变，并非突出中国技术先进；B项错误，卫星的作用是记录数据，而非详细描写漂移路径；D项错误，全文均为对已发生事实的陈述，并未对未来冰山动向进行预测。故选C。