6 .I (cook) while my sister (wash up) 7. She (sleep) at 9 o ^ clock yesterday.8. I (write) a letter yesterday.9.When

I was cooking while my sister washed upShe was sleeping at 9 o ^ clock yesterday I wrote a letter yesterday.When the lesson begins all the pupils sit at their desks./When the lesson began all the pupils sat at their desks. He wrote this novel many years ago..