zhè / zhǒng / měng / gǔ / bān / zài / yīng / ér / bèi / bù / hěn / cháng / jiàn / tōng / cháng / huì / zì / rán / xiāo / tuì

这种蒙古斑在婴儿背部很常见，通常会自然消退。

This Mongolian spot is very common on babies' backs and usually fades naturally.