正解の解説

[PASSAGE] "So the real question isn't *how* it evolved, but *why* it revolted." The professor states that the main question he will address is why Bebop emerged as a revolutionary style in response to Swing. [WHY CORRECT] Option 1 is correct because the professor explicitly states his main question is "why it revolted" against Swing, and then dedicates the rest of the lecture to detailing the "artistic motivation" and "deep-seated reasons" for this "conscious rejection." This directly covers the "primary reasons behind the development of Bebop as a reaction to Swing." [TRAPS] Option 2 is wrong because the lecture focuses exclusively on Swing and Bebop, not "all major jazz styles in the 20th century." Option 3 is wrong because while instrumentation is mentioned briefly (big bands vs. small clubs), the focus is on artistic and cultural motivations, not "technical differences in instrumentation." Option 4 is wrong because the lecture states Bebop was "deliberately not for dancing" and more complex, implying *less* commercial success and popularity compared to Swing, not widespread popularity. [TIP] For main idea questions, listen for explicit statements from the speaker that introduce the central theme or the "main question" they will address, paying close attention to opening and concluding remarks.

誤答の理由

• Option B (“A chronological history of all major jazz styles in the 20th century.”) confuses two separate points from the text.
• Option C (“The technical differences in instrumentation between Swing and Bebop bands.”) swaps the cause and effect described in the passage.
• Option D (“The commercial success and widespread popularity of Bebop music in the 1940s.”) attaches the right fact to the wrong subject.

文脈の重要表現

Watch how academic vocabulary around Jazz History signals meaning. TOEFL detail items reward readers who track tone, transitions, and precise word choice rather than surface keywords.

学習ポイント

Scan for the keyword from the question, then read one sentence around it carefully.