1. 同楼上
“我喜欢音乐。那你呢?你喜欢吗?”
"i like music,what about you? do you like it?"
2. 那 你怎么办?
"So, what can you do?"
3. Maybe you mean “なに”, or "纳尼" in Chinese...
It's actually a Japanese word, which means "What!?". It's often used by young Chinese people who watch Japanese anime a lot.
"你的答案错了"
“纳尼!?”
"Your answer is wrong."
"What!?"