Định Nghĩa và Ý Nghĩa của "you can say that again"

What is the origin of the idiom "you can say that again" and when to use it?

The origin of the idiom "you can say that again" is not precisely documented, as it is a common and informal expression used to affirm strong agreement with something that has just been said. It has been in common use for many years as a way to affirm and emphasize agreement.