Which sentence contains an error in the choice between past simple and past continuous?
I was inspecting the attic when the alarm rang.
The dog barked, ran to the gate and stopped there.
At noon both repairs were still unfinished: while one mechanic repaired the brakes, the other was flushing the radiator.✓Correct answer
At midnight, snow was falling across the empty square.
Explanation
The brakes sentence contains the error because both jobs were still in progress at noon, so the simple form should be the past continuous there. The alarm sentence correctly combines an ongoing inspection with a sudden completed interruption.