Over geologic time the central volcano becomes extinct, followed by erosion and subsidence beneath the sea surface, leaving the coral reefs as a ring around (or cap on) the submerged island remnant.

由于侵蚀和海底的下沉，经过地质时代的变迁，中心的火山已经不见踪影，而只留下珊瑚礁环绕或覆盖在沉入海底的火山岛上。

youdao

Layers of frozen sea water, known as sea ice, cap the Arctic Ocean. The ice grows dramatically each winter, and melts just as dramatically each summer.

北冰洋的冰层由结冰的海水构成，这些冰层在每年的冬天急速冻结，又在每年的夏天迅速消融。

youdao

Allen also may order BP to open the cap and let oil and gas flow via pipelines to vessels on the sea surface where it will be separated, stored and burned.

艾伦可能还会命令BP打开控油罩让油、气流通过管道输送到海面的舰船以便他们在那里能够被分离、储存和焚烧。

youdao

They spend most of their time on sea ice, this cap of ice that is floating around on the surface of the Arctic Ocean.

CNN: Polar bear now listed as 'threatened' species

Are you terrified by the melting polar ice cap, rising sea levels, extreme weather, and other growing threats from global warming?

FORBES: Want to Save the Planet? Just Slack Off at Work, Study Says

Jack Hall (Dennis Quaid) is a climatologist who realizes, as a slice of the polar ice cap slides into the sea, that the end of the world (or, at any rate, of that half of the world that drives S.U.V.s) is nigh.

NEWYORKER: The Day After Tomorrow