insoluble/ɪnˈsɑːl.jə.bəl/形容词(问题)无法解决的Traffic congestion in large cities seems to be an insoluble problem.大城市的交通堵塞问题似乎无法解决。(物质)不能溶解的These minerals are all insoluble in water.这些矿物质都不溶于水。想跟读,去练习