Matching Pairs Past Continuous: When ( Stopwatch4B, Workbook, exercise 3, page 144)Online version Matching pairs by Andronica Ribera Moruco 1 She was walking her dog 2 They were studying for a math exam 3 She was doing yoga 4 He was riding his bike when someone knocked at the door. when she saw an accident. when the earthquake started. when his telephone rang.