Problem 1: In time clauses with the Simple Past tense, what verb tense is the verb in the main clause? What verb tense is the verb in the time clause?
Problem 2: In time clauses with the Past Continuous (longer action interrupted by a shorter action), what verb tense is the verb in the main clause? What verb tense is the verb in the time clause?
Problem 3: In time clauses with the Past Continuous (two actions happening at the same time in the past), what verb tense is the verb in the main clause? What verb tense is the verb in the time clause?