Put the verbs into the correct from ( past perfect continuous) 1.we sleep for 12 hours when he woke us up. 2.they wait at the station for 90 minutes when the train finally arrived. 3.we look for her ring for two hours and then we found it in the bathroom. 4.i not walk for a long time, when it suddenly began to rain 5.how long she learn english before she went to london?