Keke learned these characters from the Chinese school.  Now she can recognize them.  Her mom taught her that the cross inside the 风 looks like the 风车，and the dots insides 雨 like the 雨点.  But for the character 云, Keke never remembered it, although LP reminded her again and again about the thing in the blue sky, “天上白白的，” 。 I think Keke did not know what 云彩 is, or she knows it but does not know its name, at least she never heard somebody speak of it. So that is why she did not know how to remember it.

Also, for the characters 龙,马,牛,羊.  She can only recognize 龙.  Probably she knows 恐龙, as for马,牛,羊, she never met one in her real life, so she has no concepts at all.

I read an article about preschool education in Germany, there, they donot usually push the kids to study much before school age.  One reason is that, they would like to preserve the creativity, and initiative of the children, otherwise, the kids brain maybe like the hard disk of the computers, only store things.  That maybe make sense, and I did not remember I learned things before going to school.