1. Our teacher was relieved when he heard that all of his students had made progress.
→ Our teacher felt reassured upon hearing that all of his students had made progress.

2. They know very well that physical education is an important school subject.
→ They are fully aware that physical education is an important school subject.

3. The mother was happy when she learned that her daughter had enjoyed herself at the party.
→ The mother felt joy upon discovering that her daughter had enjoyed herself at the party.