Помогите пожалуйста! Необходимо избрать верный ответ. 1)l was brushing my teeth

Помогите пожалуйста! Необходимо выбрать правильный ответ. 1)l was brushing my teeth when \ while my sister was making tea. 2)He was riding a horse when\ while the car drove to the stable. 3)Sue was walking along the path as\ while it started to rain. 4) you were wasting the dishes as\ I was drying them. 5) Kate was speaking to the doctor when \ while her mobile telephone rang. 6) We were discussing the film as\ while Mary was Looking thorough some magazines. 7) The waiter was carrying the tay when\ while he dropped a glass. 8) Sam was crossing the road when\ while he saw his friend at the bus stop. 9) Line and Wendy were preparing for the test as\while the postman knocked at the door. 10) The child was eating soup when while his mother was making salad. Заблаговременно громадное спасибо!!!!!!!!!!!!!!!!!!!