This is the 971st most frequent Vietnamese word.
biết
"Biết" means "to know."
In this sentence, "biết" is used to indicate "knowing" someone or being acquainted with certain knowledge about a person.
Tôi biết anh ấy là một người tốt.
I know he is a good person.
Here, "biết" is used to express the awareness or knowledge of a specific skill, in this case, cooking pho.
Tôi không biết cách nấu phở.
I do not know how to cook pho.
In this example, "biết" conveys the act of learning or acquiring knowledge about a subject, here, Vietnamese history.