She definitely had an ulterior motive in offering to help.

她主动提出帮忙, 肯定有不可告人的动机。

When this method is applied to the spiral bevel gears of an airplane engine, the results show that it is more reasonable than TCA and the precontrol method.

提出了一种在初阶段可保锥轮具有预期加载接触性能的主动方法，并将其用于某航空发动机中央传动锥轮的面综合。