你知道他送你什么吗？---the point is something to give you重点“送你的东西” 你知道他送的什么吗？---the point is something重点“什么”

What are the DIFFERENCES between these two sentences? The general meaning is the same. The difference is that the 1st one translates into > "Do you know what he sent you?" The 2nd translates into "Do you know what stuff he sent you?" 送的 is the short for 送的東酉. 的 is a possessive case acting like an apostrophe ess.