The company has made sure the books are easy to recognize.They all have bright yellow covers, with titles scrawled on black signs, like chalk on a blackboard.

• 公司为了要让这套丛书易于辨认，设计了统一的亮黄色封面，书名用草体写在黑色的底色上，就像粉笔写在黑板上一样。