I understand #1&2 but #3 and 4 confuse me.

Tanner-UNF Corporation acquired as an investment $260 million of 6% bonds, dated July 1, on July 1, 2021. Company management is holding the bonds in its trading portfolio. The market interest rate (yield) was 8% for bonds of similar risk and maturity. Tanner-UNF paid $220 million for the bonds. The company will receive interest semiannually on June 30 and December 31. As a result of changing market conditions, the fair value of the bonds at December 31, 2021, was $230 million. Required: 1. & 2. Prepare the journal entry to record Tanner-UNF's investment in the bonds on July 1, 2021 and interest on December 31, 2021, at the effective (market) rate. 3. Prepare any additional journal entry necessary for Tanner-UNF to report its investment in the December 31, 2021, balance sheet. 4. Suppose Moody's bond rating agency downgraded the risk rating of the bonds motivating Tanner-UNF to sell the investment on January 2, 2022, for $200 million. Prepare the journal entries required on the date of sale. Journal entry worksheet Record any adjustment necessary to report the bond investment in the December 31, 2021 balance sheet. Note: Enter debits before credits. Date General Journal Debit Credit December 31, 2021 Fair value adjustment Gain on investment (unrealized, NI) Record entry Clear entry View general journal Journal entry worksheet Record the sale of the investment by Tanner-UNF. Note: Enter debits before credits. Date General Journal Debit Credit January 02, 2022 Record entry Clear entry View general journal