It looks like you're working on sentence transformation. Here are some suggested revisions for each of the sentences provided:

1. **My father started working for an engineering company 15 years ago.**
-> My father has been working for an engineering company for 15 years.

2. **Jack caught a cold after walking home in the rain.**
-> Jack caught a cold because he walked home in the rain.

3. **The apartment is big. The rent is high.**
-> The apartment is big, but the rent is high.

4. **You should watch television less, or your eyes may get tired.**
-> You should watch television less; otherwise, your eyes may get tired.

5. **We don’t have enough time for relaxation.**
-> We have insufficient time for relaxation.

Feel free to adjust the transformations as needed!