The world’s biggest iceberg is on the move for the first time after being stuck to the ocean floor for 30 years. The iceberg, called A23a, is 3884 km sq in size, which is twice the size of London. It is also 399m thick, which is about two-thirds as high as the world’s tallest building, the Burj Khalifa in Dubai.

The iceberg split from the Antarctic coastline in 1986 but got stuck to the ocean floor and became an ice island. It started drifting (漂流) again in 2020 but picked up speed this year as wind and currents pushed it along faster. The iceberg has started heading past the northern tip of the Antarctic Peninsula (南极半岛) and could soon leave Antarctic waters altogether. The iceberg will most likely end up in the Antarctic “Circumpolar Current” before being pushed into a path known as “iceberg alley”.

Icebergs like A23a that end up in the Weddell sector usually follow the same path because of the movements of the Circumpolar Current, which is the strongest current in the Earth’s oceans. From there, the huge iceberg might drift towards South Georgia island, which often has big tabular (板状) icebergs sitting off its coast. The ice blocks usually get attached to the shallow continental shelf of the island, which is considered British territory. 

If A23a gets stuck near South Georgia, it might pose a problem for the millions of seals, penguins and other seabirds that live on the island. The mega berg could get in the way of the animals’ normal routes of searching for food, stopping them from feeding their young properly.

But all icebergs eventually melt and disappear, releasing mineral dust. And this dust is an important part of oceanic food chains. “In many ways these icebergs are life-giving; they are the origin point for a lot of biological activity,” said Dr Catherine Walker. The scientists will observe the movement of A23a closely.

1.Why are London and the Burj Khalifa mentioned in the first paragraph?

A To show where the iceberg comes from.

B To emphasize the enormous size of the iceberg.

C To indicate people are concerned about the iceberg.

D To suggest people in Antarctica are in danger.

解析：选B。B 推理判断题。根据第一段中的描述“The iceberg, called A23a, is 3884 km sq in size, which is twice the size of London. It is also 399m thick, which is about two-thirds as high as the world’s tallest building”这座名为A23a的冰山面积为3884平方公里，是伦敦面积的两倍，它有399米厚，大约是世界最高建筑的三分之二高，这是在形容这座冰山的体积之大。故选B。

2.Where is the iceberg A23a most likely to get stuck?

A In the “iceberg alley”.

B In the Weddell sector.

C In British waters.

D In Antarctic waters.

解析：选C。C 推理判断题。结合第二三段内容可知，冰山A23a将离开南极水域，进入一条被称为“冰山小巷”的路径，再从那里漂向南乔治亚岛，而南乔治亚岛被认为是属于英国的领土，即这座冰山最终可能会停在英国水域。故选C。

3.What does the underlined word “mega” in Para. 4 probably mean?

A Dangerous.

B Huge.

C Freezing.

D Well-known.

解析：选B。B 词义猜测题。 根据前文中出现的“The world’s biggest iceberg”以及“ the huge iceberg”可知这座冰山巨大；结合后文“get in the way of the animals’ normal routes of searching for food”这座冰山可能会妨碍动物觅食的正常路线，可推断，此处mega表示“巨大”之意。故选B。

4.In which column of a newspaper can you most probably read this article?

A Climate.

B Travel.

C Environment.

D Science.

解析：选C。C 推理判断题。本文主要介绍了世界最大的冰山，它的大小是伦敦的两倍，高度是世界最高摩天大楼的三分之二，它已经开始从南极洲漂移，并可能最终进入英国水域，冰山是关于自然环境方面的内容。因此本文最有可能出现在“环境”版块。故选C。