2 Leo used to/would like steak but he doesn't anymore.
used to → Leo used to like steak but he doesn't anymore. ("Used to" — для минулих звичок, що більше не актуальні)
4 Sam stopped during the race but I kept/ was going
kept → Sam stopped during the race but I kept going. ("Kept going" — продовжував бігти)
While I waited/ was waiting for the bus yesterday, I saw/was seeing an old friend from school.
was waiting, saw → While I was waiting for the bus yesterday, I saw an old friend from school. (Тривала дія + коротка подія)
3 We were at the beach. The sun used to come down/ was coming down and it would get/ was getting dark.
was coming down, was getting → The sun was coming down and it was getting dark. (Опис двох одночасних тривалих дій у минулому)
When we were little, we'd go/ were going to the woods every day after school.
we'd go → When we were little, we'd go to the woods every day after school. ("We'd go" = "we would go" — минула звичка)
6 Barcelona beat/beating Real Madrid 1-O yesterday.
beat → Barcelona beat Real Madrid 1–0 yesterday. (Опис конкретної події вчора — past simple)