Complete the sentences.use the past continuous and the past simple. I

Complete the sentences.use the past continuous and the past simple. I _____ in the park when I_____ my friend.( walk,see). Joe____across the road when he ___ down.( run,fall). We____ a picnic when suddenly it ___ to rain (have, begin). The scientist ___ late when he ___ a discovery. ( work, make). Mrs Johns ____ in the mall when she ____ her bag ( shop, lose). The boys ____ football when they ___ the window. ( play, break)