1. As far as I know, he is still working in Korea.             → To the best of my knowledge, he is still working in Korea.

2.  We weren’t surprised by his success.                        → It came as no surprise to us that he had succeeded

3. They cancelled the flight because of the heavy rain  → So heavily was the rain that They cancelled the flight

4. He isn’t present at the meeting, and I’m not either.    → Neither he nor I am present at the meeting

5. I only understood very little of what my teacher said → I could hardly understand what my teacher said