He is researching about a new energy source.

He is conducting research on a new energy source.

This lake is very deep.

His eyes were filled with deep sorrow.

He is deeply immersed in the study of Leninism.

She is planning a date with her current boyfriend.

He lost everything.

My boyfriend gave me a gift.

Everyone was surprised by the news.

We are focusing on the research and development of new products.