Section 283 is found on page 24 in the answer key.
In part one, there’s just a minor spelling error in sentence 2.
I.2. Your letters were pleasing to ys and our letters were pleasing to you.
Correction: Your letters were pleasing to us and our letters were pleasing to you.
And in part two, a slight grammatical error in sentence 2 as well.
II.2. Mīlitēs gladiō sē(sē) vulnerāvit.
Correction: 2. Mīlēs gladiō sē(sē) vulnerāvit.