11. 2. I didn't meet my old friend while I was staying in Prague.
3. She walked into a tree when she was talking on her mobile phone.
4. While shopping he lost his wallet.
5. When I was doing the washing-up, I broke a glass.
6.They were driving home when petrol ran out.
7.He broke the key while he was trying to open the door.
8.We weren't swim when we heard the screams.
