The continental shelf is a natural extension of the mainland, the original for the coastal plain, the latter due to sea-level rise only after indulging in underwater and become shallow.

大陆架是大陆的自然延伸，原为海岸平原，后因海面上升之后，才沉溺于水下，成为浅海。

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In a proposal issued the week before Katrina, the Department of the Interior announced it wanted to open the outer continental shelf (600 to 9, 500 feet underwater) to exploration in the next round of lease auctions.

FORBES: Open the Spigots