Exercise 1.complete the sentences below with ''when''or ''while''.
1. ......... Mrs. Scott came back to her hotel,she sat at the lobby for while.
2. I burnt my hand ........ I was cooking dinner.
3. We were walking at the countryside .......... we heard a loud,strange noise.
4. Tommy was driving at 140 km/h .......... a policeman stopped him.
5. She didn't say anything ......... I asked her what was wrong.