内联标记不能包含块级别标记。

Inline tags cannot contain block-level tags.

youdao

首先，序列不能包含其他序列。

First, they can't contain other sequences.

youdao

简单类型的值不能包含元素或属性。

A simple type cannot contain elements or attributes in its value.

youdao

These are going to be fairly common-sense definitions, but they're important, and when you get to a problem set, really nailing down what the system is, not more, nor less, in terms of the amount of stuff, that's part of the system, it's going to be often very crucial.

这些是,很常识性的定义，但是很重要，当你要解决问题时，务必要搞清楚系统是什么，它包含多少物质，不能多也不能少，这往往,是非常重要的。

麻省理工公开课 - 热力学与动力学课程节选

Normally I couldn't do that Vdp because this term would have p dV plus V dp, but we've specified the pressure is constant, so the dp part is zero.

一般情况下我不能这么写,因为这一项会包含pdV和，但是我们已经假定压强为常数，所以包含dp的部分等于零。

麻省理工公开课 - 热力学与动力学课程节选