He devoted his life to the research of science.

He is doing research on a new energy source.

He set out on a journey to quest for the truth.

He is doing his best to search for the truth.

This ancient forest has existed for centuries.

Yesterday, I reunited with an old friend after a long time.

I decided to take a paid leave.

I studied in the library with my classmate.

The plan to turn this unused land into a park is underway.

I plan to take paid leave next week.