past continuous D to give the background or set the scene for an action or event, often with while
past perfect (had + past participle) F with ever/never + superlative adjectives
used to/would G used to/didn’t use to for repeated past actions, habits and states; would for past actions and habits only
past simple A for finished actions or events in the past, or a sequence of actions
past continuous C for an action interrupted by another action in the past
past perfect (had + past participle) E for actions, events and situations that happened before another past action
past continuous B for actions in progress in the past and temporary situations
When he asked her where the Great Wall was in China, she replied ‘China’.
The escaped cows were hanging around.
One cow fell onto the tracks while the railway employees were moving them.
The Ancient Egyptians used to decorate their royal tombs.
Rush hour had just begun when a herd of escaped cows found their way into a local railway station.
It was the biggest iceberg they had ever seen.
While I was doing research, I realised that the media concentrated on negative issues.