You will be given a definition of a task first, then some input of the task.
In this task, given a sentence in the English language, your task is to convert it into the Vietnamese language.

Police had warned them about crossing into the disputed land before.
Output:
Cảnh sát đã cảnh báo họ về việc xâm nhập vào khu đất đang tranh chấp trước đó.