Paul is speaking to the Corinthians as if they were one person, so all instances of "you" here are singular. (See: [[rc://en/ta/man/translate/figs-you]])
Paul is rebuking the Corinthians who think they are better than those who heard the gospel from someone else. AT: "For there is no difference between you and others." or "For you are not superior to other people." (See: [[rc://en/ta/man/translate/figs-rquestion]])
Paul uses this question to emphasize that they did not earn the things they have. AT: "Everything that you have is what you have freely received." or "God gave to you everything that you have for free!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
Paul was rebuking them for boasting in what they had. AT: "you should not boast as if you had not done so." or "you have no right to boast!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
# as if you had not done so
The phrase "done so" refers to freeling receiving what they had. AT: "as you you had not freely received it" or "as if you had earned it"