If we remember how to form present continuous tense questions, it will be very easy to form past continuous tense questions. To form past continuous tense questions, we just need to change from is/am/are to was/were.
Structure
Helping verb (was/were) + Subject + Main verb (-ing) + Rest of the sentence1. you / sleep / when the alarm rang
2. she / prepare / for the exam
3. they / discuss / the project details / during the meeting
4. you / plan / the vacation / while waiting for the bus
5. we / analyze / the data / when the power went out
