Variational method is a branch of mathematics used to find the minimum and maximum values of functions.

I am interested in the culture of China.

He is good at reading Chinese text.

I am busy with work during the day.

I work during the daytime.

He is researching the functions of the midbrain.

He was watching the television relay.

He was relaying the soccer match on TV.

My younger brother is currently attending middle school.

He is studying the history of Central Europe.