1. As far as I know, he is still working in Korea.
→ To
2. We weren’t surprised by his success.
→ It came
3. They cancelled the flight because of the heavy rain.
→ So heavily
4. He isn’t present at the meeting, and I’m not either.
→ Neither he
5. I only understood very little of what my teacher said.
→ I could hardly
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