Hi there! As I promised, here you have the answers to the exercise on reported speech.
1. Robert boasted that he had always been good at Maths.
2. Nidia objected to paying that much for gas.
3. Belem insisted that I must see a doctor immediately or Belem insisted that I should see a doctor immediately ( in this case because you can use the construction verb + that + subject + should with the verbs insist and suggest instead of the gerund)
4. My father promised to help me with my homework the following Saturday or My father promised that he would help me with my homework the coming Saturday
5. Susan warned her children not to play with matches or they might get burned.
6. Jimmy confessed to breaking the window or Jimmy confessed to his mother that he had broken the window
I hope you have had good marks. See you all!