核心问题
I will show you (the way) how I solved the question. (钱歌川编著《英文一日一题》，pp. 44–45)
作者指出,句中的 the way how 可略为 how。作者把 how 看作是能引导定语从句的关系副词,这使我感到很陌生。
词典解答
英美的英语语法学家们都没有把 how 划为能引导定语从句的关系副词。CGEL 认为，能作为关系副词只有 where, when, why 和 that(p.1254):
能作为关系副词只有 where, when, why 和 that (p. 1254): “There is no relative how parallel to where, when, and why to express manner with an antecedent noun [4], but only [4a]:
※That's the way how she spoke. [4]
That's she spoke. [4a]
“英语里并不存在与接在先行名词之后 where, when 和 why 平行的表示方式的关系词 how。因此，不能说： That's the way how she spoke.
而必须说：
<div class="mineru-algorithm" style="white-space: pre-wrap; font-family:monospace;"> That's $\left\{ \begin{array}{l} how \\ \text{the way (that)} \end{array} \right\}$ she spoke. " (CGEL, p. 1254) </div>