The empty boat drifted out to sea.

空船向海上漂去。

It is a rule of the sea to help another boat in distress.

救助别的遇难船是海上的规则。

Such a boat is fit only for a calm sea.

这种船只适于在风平浪静的海上航行。

The sea got very rough and the boat capsized.

海的风浪变得很大，船翻了。

The little boat was swept out to sea.

小船被吹到大海的深处去了。