✨ ベストアンサー ✨
1. (had been) 過去完了形・継続
2. (just got)
3. (had never met) 過去完了形・経験
4. (had lived) 過去完了形・継続
1. Before I introduced him to Lisa, (he had already talked with her).
2. Mao (had been sleeping for one hour) when her mother came in her room.
3. Takashi (had never done volunteer work until) he entered high schoo.
4. Shohei (had been drving for three hours) when his smartphone rang.
5. (Had it stopped raining before) you arrived at the station?