几十年来，美国五大湖区的潮水在缓慢退减。

FOR decades the Great Lakes region has seen a slow ebb.

youdao

美国中北部五大湖区及密西西比河上游河谷周围的地区。

A region of the north-central United States around the Great Lakes and the upper Mississippi Valley.

youdao

美国中北部五大湖区及密西西比河上游河谷周围的地区。

A region of the north-central United States around the Great Lakes and the upper Mississippi Valley.

youdao