他正式成为了总统。

Tā zhèngshì chéngwéi le zǒngtǒng.

He officially became president.

我们的餐厅今天正式开幕。

Wǒmen de cāntīng jīntiān zhèngshì kāimù.

Our restaurant officially opened today.

今天是我正式上班的第一天。

Jīntiān shì wǒ zhèngshì shàngbān de dì yì tiān.

Today is my first official day at work.