[U]
cross the sea
横渡海洋
We left the port and headed for the open sea(= part of the sea far away from the land).
我们离开港口向公海驶去。
He was lost at sea and brought to land by another ship.
他在海上迷失了方向，被另一只船带上岸。
He travelled to New York by sea.
他乘船去了纽约。
I have a cottage by the sea.
我有一间海滨小屋。