What was happening ...?
Past Continuous
Use the past continuous to express what was occurring at a precise moment in the past. The past continuous is often used together with the simple past to express an interrupted action. The action which was interrupted is expressed using the past continuous, while the action which caused the interruption takes the past simple.
Positive Form:
Subject + to be + verb + ing + objects
The bank clearance was being issued when everything was put on hold.
Negative Form:
Subject + to be + not + verb + ing + objects
The bank account wasn't being investigated when a client came in.
Question Form:
Wh? + to be + subject + verb + ing?
Were you checking your bank balance when you got the notice your checking account was overdrawn?
Examples of What Was Happening ...
Were you checking your bank balance when you got the notice your checking account was overdrawn?
Was he visiting his local bank branch when the manager offered him a job?
The actual yield was rising when the central bank acted.
The teller wasn't checking the amount of the account overdraft when the bank manager arrived.