根据短文内容,填写所缺单词或用所给单词的正确形式填空。
Heilongjiang Provincial Museum is a great place to learn about history and culture, so following the museum rules 1. (be) very important. I often visit it with my classmates. I always get up early and arrive at the museum 2. time. Before entering, the guide tells us we 3. (must) touch any cultural relics(文物)—they are precious and easy to break.
In the exhibition halls, I walk slowly and speak 4. (soft). I never run or shout, because other visitors need a quiet environment to enjoy the displays. When I want to take photos of the dinosaur fossils, I always find a sign saying "No Photos", 5. I put my phone away at once. I also keep the hall clean and never throw rubbish on the floor.
However, my friend Lily sometimes almost forgets to turn off her flash(闪光灯). I remind her 6. (quick)—using flash is bad for the ancient paintings. The guide often tells us we must always follow such small rules 7. (protect) the museum's collections. Lily decides to set a "silent and no-flash" reminder on her phone 8. she visits a museum next time.
Visiting the museum teaches me a lot. Following the rules not only helps us have a better experience, but also protects cultural heritage(遗产) for everyone. A good habit of following the rules makes our visit 9. (happy) and more meaningful. I believe 10. we all follow the museum rules, the collections will be well-preserved for future generations. Let's remember: Respecting rules is respecting history and ourselves.

1. is
2. on
3. mustn't
4. softly
5. so
6. quickly
7. to protect
8. when
9. happier
10. if