Изберите верный вариант применяемого сказуемого (Simple Tenses, Continuous Tenses):

Изберите верный вариант применяемого сказуемого (Simple Tenses, Continuous Tenses): Peter (to try) __________ to change a light bulb when he (to slip) ____________ and (to fall) _________ .
1)tried, slipped, fell
2)was trying, was slipping, was falling
3)was trying, slipped, fell