一来二去

Explanation: Refers back to another one back, after a period of time. That the meaning gradually. 　　Usage: Joint type; as adverbials; that gradually 　　Source: Cao Xueqin, "Dream of Red Mansions," the 58th to go back one to two, two people on the fool, and reversed image is really the same as children. " 　　Examples: Later ~, gradually familiar. (Qing Shi Yukun "San Xia Wu Yi," the twenty-first back)