字段和记录的边界和XML文档的边界不匹配。

Field and record boundaries just don't match the boundaries of an XML document.

youdao

这组待选对象随后使用大小写不敏感的单词边界括起（\c\<\(...\)\>），确保只有完整的单词被匹配，而不需要关心大小写。

That set of alternatives is then bracketed by case-insensitive word boundaries (\c\<\(...\)\>) to ensure that only entire words are matched, regardless of capitalization.

youdao

如果把“engineering”拿去匹配，正则引擎会先匹配到“engineer”，但接下来就遇到了字词边界，b，所以匹配不成功。

If the regex engine is given the word 'engineering', it will correctly match 'engineer'. The next word boundary, \ b, will not match.

youdao