这是一个不稳定系统，就像尝试平衡立在指尖上的铅笔一样。

This is an unstable system, like trying to balance a pencil on your fingertip.

youdao

这是一个不稳定系统，就像尝试平衡立在指尖上的铅笔一样。

This is an unstable system, like trying to balance a pencil on your fingertip.

youdao