Who can tell? is a series of interesting popular science picture books that is suitable for young readers. There are six books in this series, including "cheetahs and leopards", "sea lions and seals", "lesser pandas and raccoons", "African elephants and Asian elephants", "butterflies and moths", and "ostriches and emus”. These animals interest children most but are difficult for children to distinguish. By presenting funny pictures and humorous dialogues in way of comparison, we introduce two kinds of animals which can be easily confused. This series can cultivate children's ability of observing, the habit of comparing and analyzing similar things, inquiring mind towards the world and the love of nature and life.