Romaji: Doushite sono jisho o kawanakatta ndesu ka. Translation: Why didn't you buy that dictionary?
Explanation: 悪い (bad) directly connects to んです. It explains that smoking is bad for the health. 毎日練習しましたから。 →right arrow 毎日練習したんです。 Minna No Nihongo Lesson 26 Renshuu B Answers
If you're studying for the JLPT, I can also provide practice questions tailored to the Lesson 26 grammar points. Romaji: Doushite sono jisho o kawanakatta ndesu ka
Grammar Breakdown: 嫌い (dislike, な-adjective) + + んです. 4.2 Answer: 日本語が下手なんです。 Romaji: Nihongo ga heta na ndesu. Translation: (Because) I am bad at Japanese. Minna No Nihongo Lesson 26 Renshuu B Answers
Lesson 26 of Minna No Nihongo is a major turning point because it introduces ～んです