你可以认真一点吗？

Nǐ kěyǐ rènzhēn yìdiǎn ma?

Can you take this a little more serious?

他很认真地在学习。

Tā hěn rènzhēn de zài xuéxí.

He's taking his studies very seriously.

他做事很认真。

Tā zuòshì hěn rènzhēn.

He works very seriously.