Because it's only when you do that, that you can talk about --  -- it's only when you do that, [that] you can talk about how we looked like and how we behaved at different times, and how those likes and looks and behaviors changed through time.
只有做到这一点之后，你才可以讨论...  只有做到这一点之后，你才可以讨论 在不同时期我们的相貌和我们的行为， 以及这些喜好、相貌和行为如何随着时间的流逝而变化，