Yalu river forms a natural （boundary) between China and North Korea.A.borderB.stringC.sp

题目：Yalu river forms a natural （boundary) between China and North Korea.A.borderB.stringC.sp

[Yalu river forms a natural (boundary) between China and North Korea., A.border, B.string, C.spot, D.zone]$[A
该题句意为：鸭绿江是中朝两国天然的分界线。border:边界、边疆。例如：They fled across the border.他们穿越边界逃走了。string:绳子。例如：He held out a small bag tied with string.他拿出一个系着细绳 的小袋子。spot:地场所。例如：He did not mention having been on the spot.他没说他当时在场。zone:区域。例如：How is the economic development zone going on?现在经济开发区怎样了?]