Tā shì dìyī gè yóu guò Yīngjílì Hǎixiá de Zhōngguórén.
He was the first Chinese person to swim across the English Channel.
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英吉利 is the older Chinese transliteration of 'English' (from 'English-li'), which is why this strait is named after the English rather than 'British' (英国). 海峡 means 'strait' or 'channel'. The French name (La Manche / 拉芒什海峡) is rarely used in Chinese.