一衣帶水
a narrow strip of water
中日兩國是～、一葦可航的鄰邦。China and Japan are close neighbors facing each other across a narrorw strip of water (or separated only by a strip of water).
一衣帶水yī yī dài shuǐ
像一條衣帶那樣窄的水。形容兩地非常近，僅一水之隔。a narrow strip of water, a strip of water