Children were not colour-coded at all until the early 20th century: in the era before domestic washing machines all babies wore white as a practical matter, since the only way of getting clothes clean was to boil them.
直到20世纪初，儿童才开始被按颜色进行区分：在家用洗衣机出现之前的时代，所有婴儿都穿白色衣服，这在实际中是合理的，因为当时唯一清洁衣物的方法就是煮沸。
例句取自历年考研英语真题，翻译为机器生成，仅供学习参考。