fill in the blanks with as / since / because or because of

Here are the completed sentences: 6. The language learners formed study groups because they wanted to support each other. 7. She couldn't attend the party because she was feeling unwell. 8. They arrived late to the meeting because of the traffic jam. 9. Because of his hard work, he was promoted to a higher position. 10. Because of the heavy rain, the match was postponed.