3. Teacher: Which letter goes after “A”?
4. The girl said: “I’m sorry. It’s late”.
5. She asked : “What subject do you like?”

3 Teacher asked pupils which letter goes (went)after A?

goes-здесь правильнее,но ты напиши оба варианта

4 The girl apologized and said that was late.

5 She asked us what subject we liked.