Vul de juiste vorm van het werkwoord tussen haakjes in, let goed op of het past simple of past continuous moet zijn.
1. She _________ (to study) when her best friend called.
2. I __________ (to fall) when I was hiking last summer.
3. They ___________ (to drive) when they heard the news.
4. They __________ (to sleep) when the dog suddenly barked.
5. He _________ (to whisper) while she was trying to pay attention