1. Susan mustn't have known about the surprise party.
- must have done sth: chắc chắn làm gì đó (trong quá khứ)
2. There have been changes in the train timetable.
3. I would rather live here.
- would rather + V: muốn làm gì
4. Today Gina broke the record for the highest jump.
- break the record: phá vỡ kỉ lục
5. Most medical students graduate when they're 25.
- graduate: tốt nghiệp