根据句意，从方框中选择恰当的单词填空，每个限用一次，有的需要变换形式。
| true, when, while, shock, hear |
1. When I ________ the news, I was surprised.
2. ________ I was watching TV, my father came back home.
3. What were you doing ________ it started to rain?
4. Tell me the ________, or I will be angry with you.
5. Everyone was ________ to see the accident.