一片汪洋 is an idiom
一片汪洋yī piàn wāng yáng
形容水面辽阔，水势浩大。
Word breakdown for “一片汪洋”: Open in Reader →
一HSK 1top 500Among the 500 most common words 1.one2.single3.a (article)4.as soon as+3 more+4 more 片top 2kAmong the 2,000 most common words 1.disk2.sheet
片HSK 2top 2kAmong the 2,000 most common words 1.thin piece2.flake3.a slice4.film+10 more+11 more