But then we develop the ego and superego to balance the id.
但是随后我们发展自我和超我来平衡本我。
英语百科
Independent and identically distributed random variables
（重定向自I.i.d.）
In probability theory and statistics, a sequence or other collection of random variables is independent and identically distributed (i.i.d.) if each random variable has the same probability distribution as the others and all are mutually independent.