先生が何んなに苦しんでゐるか、是も私には想像の及ばない問題であつた。
translation
It was a problem that I could not even imagine how much Sensei was suffering.
kanji (pronunciations & definitions)
| 先生: teacher (せんせい), instructor, master, sensei, title or form of address for a teacher, master, doctor, lawyer, etc. | 何: what (なに), what (ナニ), you-know-what, you-know-what, that thing | 苦: pain (く), anguish, suffering, distress, anxiety | 是: here (ここ), this place, this point, here, now |
| 想像: imagination (そうぞう), supposition, guess | 及: and (および), as well as | 問題: question (e.g. on a test) (もんだい), problem, problem (e.g. societal, political), question, issue |