问题描述：
2. Shanghai, which means “above the sea”, is on the Whangpoo River, the lowest tributary at the mouth of the Yangtze. Whereas the territorial limits of Greater Shanghai, 320 square miles by government grant, reach up to the confluence of the two waters, the main city itself sits astride the Whangpoo, ten miles to the interior. Cosmopolitan Shanghai was born to the world in 1842 when the British man-of-war Nemesis, slipped unnoticed into the mouth of the Yangtze River, reduced the Woosung Fort and took the city without a fight.
问题解答：
上海，意思是“海上”，是黄浦江上，长江出口的最低的支流上，如果仅限于整个上海区，官方测有320平方米，延伸出两条支流，主要城市跨过黄浦，距内部十米。世界大都市上海起约1842年，当英国复仇战时， 进长江的嘴滑倒未被注意，减少了Woosung贸易，不用吹灰之力得到了城市
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