age coating老化: age; ageing; burn-in; prebur ...变黑: blackening; blacking; subdui ...层: I storey; tier; stratum老化变色: age color; age colour; weather stain老化变硬: age hardening下载手机词典可随时随地查词查翻译关注微信公众号：chachacidian，回复:老化变黑层，即可在微信中查询翻译
