what’SUP 要怎麼回覆？

Here are some possible responses:

1. Awesome! 真棒！
2. Pretty good. 還不錯喔！
3. Not too shabby. 還行呢。
4. Not much going on. 沒發生什麼特別的。
5. It's okay. 就這樣吧。
6. Same as always. 照常啊。