Observational studyaims at the approach to a dynamic system whose equation is undeterminable.

该方程在有限时段上采样值与给定序列重合。

He recalls a mother in her late 20s who came to him because she had an inoperable defect in her aorta that would rupture at some undeterminable time in the future, killing her instantly.

“认为，激烈面情绪有这样作用，它可以使正常活动停止，以可以在一段时间内专注于某些事物”，他这样说到。