1. The train had already left when I got to the station.
2. I walked home yesterday because I had lost my bike key.
3. I had never seen kangaroos before I went to Australia.
1. My uncle had been a smoker for thirty years when he quit smoking.
2. I had worn these glasses for three years until I bought a new pair.
3. I was tired because I had been playing soccer for two hours.
1. He said that he had bought that watch a week before.
2. I couldn’t understand at first what had happened.
1. I will have finished reading this book by next weekend.
2. If I take that test again, I will have taken it three times.
3. I will have stayed in Singapore for three weeks next Sunday.
1. When Machiko came back[home], her husband had already made dinner.
2. We had been talking on the phone for an hour when my phone ran out of power.
3. The old man said he had retired ten years before.
4. By the time I get there, the tickets will have sold out.
ここでのポイントは〈had＋過去分詞〉ですね。あとは、 過去完了進行形〈had been -ing〉、 未来完了形：〈will have＋過去分詞〉もここでのポイントとなります。