Wǒ yīnɡɡāi chūfā le.

我应该出发了。

I should be on my way now.


Notes:

我(wǒ): I

应该(yīnɡɡāi): should

出发(chūfā): to set out

了(le): particle word

Example:

A：我应该出发了

     Wǒ yīnɡɡāi chūfā le.

     I should be on my way now.

B：好，再见。

     Hǎo，zàijiàn.

     OK, see you.