1. he was sitting on the bus when it crashed
2. the boys were playing in the park when it started
3. She finished (?) her work while her mother was watching tv
4. the young boy was skiing when she broke her leg
5. jane cut her finger while he was making dinner.
wydaje mi się, że tak będzie ok
jeśli chodzi o odp. Essente to na pewno nie wszędzie będzie past simple, a "cut" nie odmienia się na cutted, w I, II i III formie jest cut ;)