1)While I was coping the exercise, my friends were describing a picture.
2)When we came in, the children were cleaning their desks.
3) We met her at the bus stop. She was waiting for the bus.
4)Some of the children were skiing while other children were skating. Everybody was having a lot of fun.
5)When we came the family was getting everything ready for Christmas. Bob and Helen were decorating the Christmas tree.
6) The girls were feeding the birds in the garden while the boys were making a bird-house.