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

该方程组解在有限时段上采值与给定序列重。

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.

“为，激烈面情绪有作用，它可以使们正常活动停止，以便们可以在一段时间内专注于某些事物”，他说到。