Ответ:
1. We hadn't finished the project by monday.
Had we finished the project by monday?
2. Rick hadn't written his CV by 5 o'clock.
Had Rick written his CV by 5 o'clock?
3. The students hadn't learnt all the topics by the time of the exam.
Had students learnt all the topics by the time of the exam?
4. The secretory hadn't typed the letter before the manager asked.
Had the secretory typed the letter before the manager asked?
5. It hadn't rained before.
Had it rained before?