“难解的”怎么读？

令人难解的是, 他竟一直保持沈默.Unaccountably, he kept silent.脚注阐明了文中难解的段落.Footnotes illuminated the difficult passages of the text.有关范数和谱的问题多半是难解的.Questions about norms and spectra are likely to be recalcitrant....

“难解的”的英语可以翻译为：unintelligible，mysterious，abstruse，cramp，enigmatical ...