=>

8. Everybody likes him because he is nice and helpful./He is nice and helpful, so everybody likes him.

-> because S V: bởi vì

9. He is not lazy, so he will get good marks./Because he is not lazy, he will get good marks.

-> so: vì vậy, vậy nên

10.  We were very tired, but we were happy after our flight to Sydney./Although we were very tired, we were happy after our flight to Sydney.

-> but: nhưng

11. He got the job although he had no qualifications./He had no qualifications, but he got the job.

-> although S V: mặc dù

12. Although she was sad, she smiled at everyone./She was sad, but she smiled at everyone.

-> Although S V: mặc dù