Here are the completed sentences using the provided prompts:

1. Jim is on holiday and so is Carol. **(Both)** Jim and Carol are on holiday.
2. George doesn't smoke and he doesn't drink. **(Neither)** George smokes neither and drinks neither.
3. Jim hasn't got a car; Carol hasn't got a car, either. **(Neither)** Neither Jim nor Carol has a car.
4. It is a very boring film. It is very long too. **(Not only)** It is not only a very boring film, but it is also very long.
5. She didn't write and she didn't phone. **(Neither)** She wrote neither did she phone.
6. His parents as well as his brother are going to Halong Bay next Sunday. **(Both)** Both his parents and his brother are going to Halong Bay next Sunday.
7. Helen lost her passport at the airport. She also lost her wallet there. **(Not only)** Helen lost not only her passport at the airport but also her wallet.
8. I haven't got time to go on holiday and I haven't got any money. **(Either/Neither)** I haven't got either time to go on holiday or money.
9. On Friday evening, sometimes I go to the cinema, sometimes I stay at home and watch TV. **(Either)** On Friday evening, I either go to the cinema or stay at home and watch TV.
10. She was really frightened when hearing the noise from the forest and so did I. **(Both/Together with)** Both she and I were really frightened when hearing the noise from the forest.
11. I like Tom and I also like Peter. **(Both)** I like both Tom and Peter.
12. It is the cheapest as well as the nicest watch. **(Not only)** It is not only the cheapest watch but also the nicest.
13. I don't like either horror film or action film. **(Neither)** I like neither horror films nor action films.