Grammaire anglaise : Third Conditional et modaux de spéculation

Rewrite the following sentences using the prompts provided to express hypothetical situations in the past (third conditional) or speculation about past events using modal auxiliaries like 'might have', 'could have', or 'should have'. Ensure your grammar reflects the complexity required for a B2 level.

1. She didn't study for the exam, so she failed. (Rewrite starting with: If she had...)
2. It is possible that he missed the train because he arrived late. (Rewrite using a modal of speculation: He might...)
3. The company made a profit increase of $15\%$ last year, but the analysts had predicted it would be much lower. (Rewrite using a modal indicating an event that occurred contrary to expectations: The analysts should have...)