I started living in this city 10 years ago. →

I have lived in this city for 10 years.

We met a famous author. We were visiting the museum. (while)

While we were visiting the museum, we met a famous author.

Studying history is important. →

It is important to study history.

You should take an umbrella, but you can also wear a raincoat. (or)

You should take an umbrella, or you can wear a raincoat.

I last saw her in 2015. →

I haven't seen her since 2015.

She began to learn the piano when she was 5. →

She has been learning the piano since she was 5.