先生はそのテーマを詳しく説明しました

先生: teacher, dr, doc, sir, doctor, professor, sensei, master, instructor
は: a, the, is, am, are, will
その: the, that, its, those
テーマ: theme, subject, topic, themed, thematic
を: o, the, to, wo
詳しい: familiar with, detailed, specific, exact, precise, thorough, explicit, specified, finicky
説明: explain, explanation, described, description, discuss, illustrate, version, exposition
し: and, shi, four, death
ます: will, to be, i will, to make, to do, to have
た: the, was, ta, da, other