ocean 
英 [ˈəʊʃən]  美 [ˈoʊʃən] 
n. 大海；洋；极大量

例句:
They spent many days cruising the northern Pacific Ocean. 

他们在北太平洋航游了很多天。

the Indian Ocean 

印度洋

There were few sights as beautiful as the calm ocean on a warm night. 

鲜有景致能与温暖夜色下风平浪静的大海媲美。

I went down to the ocean and took a swim. 

我下海游了个泳。

the seas and oceans of the world 

地球上的海和洋