They look spotlessly clean throughout their lives.
出自-2011年12月听力原文
柯林斯高阶英汉双解学习词典释义
ADJ-GRADED
极其干净的;一尘不染的
Something that is spotless is completely clean.
例句
Each morning cleaners make sure everything is spotless...每天早晨,清洁工们会把一切都打扫得干干净净。Even in the most spotless homes, carpets need regular cleaning to keep them looking good.即便是在最干净的房子里,地毯也需要定期清洁以保持美观。