what’SUP 要怎麼回覆？

Here are some possible responses:

1. Awesome! 很棒啊
2. Pretty good! 很好喔
3. Not too shabby! 還不錯囉
4. Just the usual. / Not much going on. 沒什麼啊
5. It's okay. / Just living life. 還行囉
6. Same as always. / Nothing new here. 老樣子啊