“Một nghề cho chín còn hơn chín nghề” is an idiom advising people to focus on developing or mastering a career or a skill.
“Chặt chém” or “chém” is a slang word that means to make someone pay more for something than it is worth.
“Kỷ lục” is a Sino-Vietnamese word that is often used as a noun to refer to the highest achievement achieved.
“Vì … nên …” is a pair of conjunction words used to connect two clauses of a sentence, in which the two sentences have meanings indicating the cause-effect relationship.
Câu (verb): to fish, catch fish, shrimp, etc. with a fishing rod.
“Của rẻ là của ôi” or cheapest is dearest indicates that cheap/inexpensive things are often of poor quality because the value of the goods is often compatible with its price.