How much is the mass of this object?

He lifted the big box with both hands.

We threw a party to celebrate the completion of the project.

The project has successfully completed.

He declared a win in mahjong.

He achieved a win in mahjong with astonishing skill.

He is good at winning in mahjong.

He has the ability to control the command zone.

I am writing a letter.

He is good at playing the piano, just like a pianist.