Helicopters fly in appalling weather to succour shipwrecked mariners.直升机在恶劣的天气条件下起飞前去援救遇难的船员。Mariners were also able to fix their latitude by using an instrument called astrolabe.海员们还可使用星盘这种仪器确定纬度。The ancient mariners tr...
水能把樟脑从其酒精溶液中淀析出来.Water precipitates camphor from its alcoholic solution.樟脑在酒精中可以溶化.Camphor is soluble in alcohol.樟脑溶于酒精而不溶于水Camphor dissolves in alcohol, but not in water....