Setze must (müssen) ins Simple Past  (must had to)
1. You must bring your mobile phone. (Simple Present)
1. You your mobile phone. (Simple Past)
The pupils must be at school at 8 o'clock. (Simple Present)
2. The pupils at school at 8 o'clock. (Simple Past)
3. We must be quiet in the hospital. (Simple Present)
3. We quiet in the hospital. (Simple Past)
4. You must keep your dog on a lead. (Simple Present)
4. You your dog on a lead. (Simple Past)
5. You must play softball outside. (Simple Present)
5. You softball outside. (Simple Past)
6. You must pay at the entrance. (Simple Present)
6. You at the entrance. (Simple Past)
7. The pupils must give good presentations. (Simple Present)
7. The pupils good presentations. (Simple Past)
8. Lily must write clearly. (Simple Present)
8. Lily clearly. (Simple Past)
9. We must take the Tube. It was quicker. (Simple Present)
9. We the Tube. It was quicker. (Simple Past)
10. We must change at Victoria Station. (Simple Present)
10. We at Victoria Station. (Simple Past)