So, Freud believed there were five stages of personality development, and each is associated with a particular erogenous zone.

弗洛伊德认为人格发展,分为五个阶段，且每个阶段都与特定的动欲区有关。

耶鲁公开课 - 心理学导论课程节选

Well, it really happens throughout development and it happens from the first stages.

这一过程不仅贯穿整个发育阶段,并且于胚胎发育伊始就存在

耶鲁公开课 - 生物医学工程探索课程节选