下列各句中各有一处错误请指出并改正

问题描述:

下列各句中各有一处错误请指出并改正
1.What were your sister doing at this time yesterday? 2.Cindy was doing shopping while her mother called her up.3.The boy was talking on the phone when the alien arrivedin.4.When the plane took off he drove his car along a small road.5.The girl was riding a bike when she saw the alien to get out.

1.What was your sister doing at this time yesterday?2.Cindy was doing shopping when her mother called her up.3.The boy was talking on the phone when the alien arrived.4.When the plane took off he was ...