Conditionals et modaux : exercices d'application

Rewrite the following sentences using the specified grammatical structures to convey the intended meaning accurately.

1. I am certain that Sarah did not lose her keys because I saw them on the table just now. (Use a modal of negative deduction for the past: $must/can't + have + V-ed$).
2. My car broke down, so I was late for the meeting. (Rewrite as a 3rd conditional: $If + had + V-ed$, $would have + V-ed$).
3. You are not a professional athlete, so you do not have to follow such a strict diet. (Rewrite as a 2nd conditional: $If + V-ed$, $would + V_{base}$).