四大皆空 All is vanity. 四海之内皆兄弟 All are brothers within the four seas. 四面八方 These folks come from in all directions (far and wide. there and everywere. length and breadth) 四海为家 I don t know where Jack is now. in my mind, he is a person who is here today and gone tomorrow. 未雨绸缪 take precautions before it is too late 目不识丁 not know A from B / an illiterate 失败为成功之母 Failure is the mother of success. 失之毫厘，差之千里 A miss is as good as a mile. 只要功夫深，铁杵磨成针 Little strokes fell great