1·The DOM specification covers all types of manipulations of a document representation, but it does not cover issues such as parsing a document and generating text output.
DOM 规范涵盖了文档表示的所有类型的操作，但是它没有涉及例如对文档的语法分析和生成文本输出这样的问题。
2·Ideally, you should be using these functions to do string manipulations better and pushing more application logic into the SQL layer, rather than implementing the same logic in your application.
理想情况下，应该使用这些函数更好地执行字符串操作，将更多的应用程序逻辑植入sql层而不是在应用程序中实现这些逻辑。
3·I was always having to refer to the API documentation to do even the most basic XML tree manipulations; nothing was intuitive, and almost every operation was complex.
甚至是为了进行最基本的xml树操作，我总是不得不参考api文档；没有任何东西是凭直觉的，而且几乎每个操作都很复杂。
4·For if these increases of income or utility are reduced to being infinitesimal, one can use both the symbolism and the powerful manipulations of the differential calculus.
因为，如果这些收入或效用的增加可以化为无穷小，那我们既能使用符号表示，也能利用微分学强大的操作了。
5·The last operation is particularly useful because it lets us perform symbolic manipulations on the tree.
最后一项操作尤为有用，因为它允许我们在树上执行符号操作。