单选题 His compass proved______ to him when he was lost in unknown country.
【正确答案】 C
【答案解析】解析:valuable a.宝贵的;贵重的,有价值的。precious a.珍贵的,贵重的。precise a.精确的,准确的。preferable(to)a.更可取的,更好的,更合意的。