He apologized from the bottom of his heart.

His heart is always filled with kindness.

He meditates every day to keep a calm mind.

He studied relentlessly to pass the exam.

For some reason, I can't convert this sentence.

I've helped him many times, so if you show someone favor, they will return it. I'm sure he will help me too.

My father has been suffering from sciatica for a long time.

This road is a dead end.

I commute to work every day using public transportation.

I went to the station through the underground passageway.