如果当前字母的下标和字符串的长度相等，那么这个变量是一个空字符串。

If the index of the current letter is equal to the length of the string, this variable is an empty string.

youdao

因为通常不在标记中使用它们，类型名称可以与足够的词根和修饰语连接起来，从而在不必产生长标记的情况下标识合适的域。

Because they are not usually used in tags, type names can be concatenated from sufficient roots and modifiers to identify the appropriate domain without necessarily causing long tags.

youdao

我建议如下标签：垃圾、与别人有关的东西、活动、归档、阅读、保存待用和要买的东西之类的。

Irecommend these categories: trash; refer out to someone else; action; filing; reading; holding for later reference or action; and possibilities of things todo, buy, etc.

youdao

And this spin magnetic quantum number we abbreviate as m sub s, so that's to differentiate from m sub l.

这个自旋磁量子数我们把它简写成ｍ下标ｓ,以和ｍ小标ｌ有所区分。

麻省理工公开课 - 化学原理课程节选

n l So negative e, which is sub n l, because it's a function of n and l in terms of quantum numbers.

也就是负的，E，下标是，因为它是一个,关于量子数，n，和，l，的函数。

麻省理工公开课 - 化学原理课程节选