Cách sử dụng
The expression "be lost in something" means to be very engaged or absorbed in an activity or thought to the point that you lose track of time or surroundings. For example, if you are watching a movie that is so interesting that you forget everything else around you, you can say "I was completely lost in the movie." It can also refer to being confused or not understanding something; for instance, "I'm lost in this math problem, I don't know how to solve it."