bosom friend，亲近的兄弟，知己至交的兄弟。

He is one of my bosom friends.

他是我的至交。

Within the Four Seas，四海之内。

Within the Four Seas means

within the territory of China.

The ancient Chinese thought

China’s territory was surrounded

by the Four Seas.

四海之内，即古代我国边境以内。

If you have a bosom friend within

the Four Seas, even at world’s

end he remains close to you.

国内存至交，天边若比邻。

If you drink with a

bosom friend,

a thousand cups are too few.

If you argue （争持）with a

man, half a sentence is too much.

酒逢至交千杯少，话不投机半句多。