一脫拉庫 黃金閱讀 問題T^T - 英檢

Green Iceberg

The ice shelf cores, with a total length of 215 meters (705 feet), were long
enough to penetrate through glacial ice—which is formed from the compaction
of snow and contains air bubbles—and to continue into the clear, bubble-free
ice formed from seawater that freezes onto the bottom of the glacial ice. The
properties of this clear sea ice were very similar to the ice from the green
iceberg. The scientists concluded that green icebergs form when a two-layer
block of shelf ice breaks away and capsizes (turns upside down), exposing the
bubble-free shelf ice that was formed from seawater.


6. According to paragraph 4, ice shelf cores helped scientists explain the
formation of green icebergs by showing that

○the ice at the bottom of green icebergs is bubble-free ice formed from
frozen seawater

○bubble-free ice is found at the top of the ice shelf

○glacial ice is lighter and floats better than sea ice

○the clear sea ice at the bottom of the ice shelf is similar to ice from a
green iceberg

答案是4

這題我完全看不出來關鍵在哪裡耶

增亮的那句要怎解啊??

Paragraph 4: A green iceberg that stranded just west of the Amery Ice Shelf
showed two distinct layers: bubbly blue-white ice and bubble-free green ice
separated by a one-meter-long ice layer containing sediments. The green ice
portion was textured by seawater erosion. Where cracks were present, the
color was light green because of light scattering; where no cracks were
present, the color was dark green. No air bubbles were present in the green
ice, suggesting that the ice was not formed from the compression of snow but
instead from the freezing of seawater. Large concentrations of single-celled
organisms with green pigments (coloring substances) occur along the edges of
the ice shelves in this region, and the seawater is rich in their decomposing
organic material. The green iceberg did not contain large amounts of
particles from these organisms, but the ice had accumulated dissolved organic
matter from the seawater. It appears that unlike salt, dissolved organic
substances are not excluded from the ice in the freezing process. Analysis
shows that the dissolved organic material absorbs enough blue wavelengths
from solar light to make the ice appear green.

7. Why does the author mention that “The green ice portion was textured by
seawater erosion”?
○To explain why cracks in the iceberg appeared light green instead of dark
green
○To suggest that green ice is more easily eroded by seawater than white ice
is
○To support the idea that the green ice had been the bottom layer before
capsizing
○To explain how the air bubbles had been removed from the green ice


這題我選1 因為1是我唯一可以看得出來的內容

我也知道一定不會是要問這麼簡單的東西 囧 但是就是不敢選其他的

但為什麼是3啊??


考試的時候應該怎麼樣去找關鍵句呢?

拜託各位大大提供解法

謝謝 <(_ _)>

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