Answer :
Answer:
Sure, here are the compound sentences transformed into complex sentences by replacing the coordinating conjunctions with suitable subordinating conjunctions:
1. I completed my assignment **before** I went to play.
2. **Because** it was freezing, I wore a jacket.
3. **Although** he is unwell, he helps his sister with her homework.
4. **If** you need to perform well, you need to practice more.
5. **Since** it was foggy, we took the car.
6. **Because** my car ran out of gas, I walked to the nearest gas station.
7. **Because** she was very sick, we took her to the hospital.
8. **While** he worked in a bookstore, he studied Spanish at school.
Explanation:
1. After I completed my assignment, I went to play.
2. Because it was freezing, I wore a jacket.
3. Although he is unwell, he helped his sister with her homework.
4. Unless you practice more, you won't perform well.
5. Since it was foggy, we took the car.
6. When my car ran out of gas, I walked to the nearest gas station.
7. Because she was very sick, we took her to the hospital.
8. While he worked in a bookstore, he studied Spanish at school.