你最好馬上離開。

You had better leave at once.

Source: Tatoeba

Sentence Composition

=1 你 nǐ you (informal, as opposed to courteous 您 nín)
=1 你 nǐ you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)
2 最好 zuìhǎo
  1. best
  2. had better ...; it would be best to ...
3 馬上 mǎshàng
  1. at once
  2. right away
  3. immediately
  4. on horseback (i.e. by military force)
4 離開 líkāi to depart; to leave