你曾是我的全部你曾是我的一切
[nĭ céng shì wŏ de quán bù nĭ céng shì wŏ de yī qiè]
You were once everything to me conveys strong sentiments about a significant past relationship where one party meant everything to the other, filled with nostalgic and bittersweet feelings over what used to be important in life but possibly no longer holds the same weight.