2[countableC]HEO a large area of salty water that is mostly enclosed by land 内海
the Mediterranean Sea
地中海
3sea of somethingLOT/LARGE NUMBER OR AMOUNTa very large number of people or things that all look similar 大量某物,一大片某物
He looked out at the sea of faces.
他放眼望去,人海茫茫。
4(all) at seaCONFUSEDconfused or not sure what to do 困惑,茫然不知所措
Living in a foreign country can mean you’re always at sea about what’s going on.
生活在异国他乡可能意味着你对周围的事总是茫然不知所措。
Examples from the Corpus
(all) at sea• This week, however, when you find yourself all at sea, you may wonder whether you've chosen well.• We are glad to be with them again, especially when they are at sea.• A girl from near his village in Trondheim fell ill the first day at sea.• His eyes were an astoundingblue and his complexion was ruddy from a life spent mostly at sea.• Down to the beach to see the oilrigsat sea.• Teredo, or shipworm, can have a devastating effect on the hulls of woodenshipsat sea.• At worst, they can sink or lose their nuclearwarheadsat sea.
5the seasliteraryHAAL the sea – used especially when you are not talking about a particular ocean 海,大海〔尤用于泛指〕