'She enjoys playing tennis, but he prefers basketball.'' - Here 'but' is -

• She enjoys playing tennis, but he prefers basketball. - Here 'but' is - Co-ordinate clause. 

• Co-ordinate clause : 
- Two independent clauses "She enjoys playing tennis" & "he prefers basketball" are connected by the coordinating conjunction "but."
- দুই বা ততোধিক সমমানের principal clause যখন Co-ordinating conjunction দ্বারা যুক্ত হয়ে compound sentence গঠন করে তখন তাদেরকে Co-ordinate clause বলে।
- Co-ordinate clause সাধারণত and, or, so, but, yet, otherwise, not only-but also ইত্যাদি Co-ordinating conjunction দ্বারা যুক্ত হয়।