1. I haven't had a letter from Helen since May. (he)
-> He said (that) he hadn't had a letter from Helen since May.
2. I'll buy you an MP3 player for your birthday. (he)
-> He said he would buy me an MP3 player for my birthday.
3. Don't buy useless gadgets. (my parents)
-> My parents told me not to buy useless gadgets.
4. I'm so depressed because I failed the exam. (she)
-> She said she was so depressed because she had failed the exam.
5. Where did you buy your laptop? (she)
-> She asked where I had bought my laptop.
6. You must hand your essays in by Friday. (the teacher)
-> The teacher told us that we had to hand our essays in by Friday.
7. Someone broke into my car and stole my stereo. (he)
-> He said someone had broken into his car and stolen his stereo.
8. The children are making too much noise. (she)
-> She said the children were making too much noise.
9. Remember to call me later. (Tom)
-> Tom told me to remember to call him later.
10. Can you help me with this exercise? (Sally)
-> Sally asked me if I could help her with that exercise.
11. How much did Mark pay for his new TV? (Jim)
-> Jim asked how much Mark had paid for his new TV.
12. Take the faulty radio back to the shop. (my dad)
-> My dad told me to take the faulty radio back to the shop.