同一

I'm babysitting my sister.

我要照看我的妹妹。

In order to indicate the difference in the molecular structures,the reduced topological index is defined,which is the ratio of the topological index of a molecule and that of the n...

为更突出地表达分子间的结构差异，定义了对比拓扑指数，即烷烃分子的拓扑指数与同碳数正构烷烃的拓扑指数之比。