1£®Sweeping the classroom had been finished(finish) when the teacher returned from the office.

2£®The work had been done(do) before he came back.

3£®John and Jane had known(know) each other for a long time before their marriage.

4£®I had intended(intend) to call on you£¬but was prevented from doing so.

5£®A rescue worker risked his life saving two tourists who had been trapped(trap) in the mountains for two days.

6£®I was sent to the village last month to see how the development plan had been carried(carry) out in the past two years.