Cách sử dụng
The expression "know somebody/something backwards" means that you know a person, place or thing very well and thoroughly. It is often used to express a high level of familiarity with a subject. For example, if someone says "I know this city backwards", they mean that they know every street, building and landmark in that city. Similarly, if someone says "I know my best friend backwards", they mean that they know that person very well and understand them inside out. This expression can be used in both formal and informal settings.