在你所问的句子中，however是一个连接副词。即对于主句而言起从属连词的作用，同时对于从句而言有起到副词的作用，多修饰一个形容词/副词/动词。
这是高考常考考点，高考真题：
1. If we work with a strong will, we canovercome any difficulty, _____ great it is. A.what B.how
C.however D.whatever (1995—23)
答案：C
2. ______ Mother will wait for him to havedinner together.
A. However late is he B. However he is late
C. However is he late D. However late he is (1997—21)
答案：D

《朗文英语语法》认为however引导让步状语从句时是“连词”。该书在第1.50节论述“让步状语从句”时指出：让步状语从句使句子具有对比的因素，因此有时也称它为对比从句(contrast clauses)。它们一般由下列连词引导：although (虽然)，considering (that) (就…而论，考虑到)，though (虽然)，even though (即使)，even if (即使)，much as (虽然很…)，while (虽然)，whereas (鉴于)，however much / badly / good (无论多么多 / 多么坏 / 多么好等)，no matter how (不管如何)，no matter how much (不管有多少)。在口语中，even though (即使) 可能比though / although用得更多：

However far it is, I intend to drive there tonight 不管有多远，我今晚也要开车到那儿去。