Cách sử dụng
"Tack on" means to add something extra to something that already exists. For example, if you are building a birdhouse and decide to add a perch, you could say "I am going to tack on a perch to the birdhouse." It can also be used in more abstract situations, such as when adding extra fees or charges to a bill. Essentially, it means adding something that wasn't there before.