Put the verb in the past simple or past continuous.
PAST SIMPLE - TIME EXPRESSIONS
PAST CONTINUOUS - TIME EXPRESSIONS
yesterday, the day before yesterday, yesterday morning, two days (weeks, years) ago, last week (month, year), in 1999,
the other day, then, when I met her two days ago.
yesterday at three o'clock, all day, this time last year, all morning (evening), from 12 to 14, still, while It was raining at two o'clock.
The past simple and the past continuous tense are often used together. The past simple describes the action or events and the past continuous describes a longer, 'background' action or situation. When she woke up this morning it was raining. PS + PC
Often, the 'action' described by the past simple interrupts the 'situation' described by the past continuous. The old man fell down while he was crossing the street. PS + PC
1) were playing/started 2) didn't learn 3) fell/was painting 4) was still doing 5) cooked
6) saw 7) were having 8) was reading/was preparing 9) were you doing 10) made