“难解的”造句

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.