前已指出：我们主要关心的是用线性、时不变微分方程作为实用的模型系统。

We have already stated that our main concern will be the study of systems for which linear, time-invariant differential equations provide a useful model.

youdao

前已指出：我们主要关心的是用线性、时不变微分方程作为实用的模型系统。

We have already stated that our main concern will be the study of systems for which linear, time-invariant differential equations provide a useful model.

youdao