Simple past tense:
* The cat was sleeping on the couch.
* He was late for work.
* The weather was beautiful yesterday.
Past progressive (continuous) tense:
* She was walking her dog in the park.
* We were watching a movie when the power went out.
* They were studying for their exams.
Past perfect tense:
* I was surprised to find out she was already married.
* He was exhausted because he had been working all day.
* The house was quiet because everyone had gone to bed.
Other uses:
* What was your name again? (Asking for information)
* That was a great movie! (Expressing an opinion)
Remember that "was" is the past tense of the verb "to be." You can use it in many different ways to describe events or states of being in the past.