adj.永恒的；无穷的；可靠的

Their discipline and good behaviour was unfailing. 他们的纪律和良好行为始终如一。

She fought the disease with unfailing good humour. 她始终抱乐观态度同疾病斗争。

Nature is always an unfailing fountain of inspiration. 大自然永远是灵感的泉源。

Everyone admired her patience and unfailing good humour. 人人都佩服她的耐心和永不衰减的好脾气。

adv.无穷尽地；可靠地；不倦地