应该是后面一句：But what good that would do 意为：但是那将会带来什么好处呢.因为你后面用的是句号,应该用陈述语序.
如果是问号就为第一句But what good would that do?
因为what这个疑问词作的是后面的宾语,do what
具体分析如下：
特殊疑问句有两种语序：
1．如疑问词作主语或主语的定语,即对主语或主语的定语提问,其语序是陈述句的语序：
Who is singing in the room﹖
whose bike is broken﹖
2．如疑问词作其他成分,即对其他成分提问,其语序是：特殊疑问词+一般疑问句【特殊疑问词+be/助动词/情态动词+主语+谓语What does she like?What class are you in﹖Where are you from﹖
What time does he get up every morning﹖
How do you know﹖
- -!其实口语中两者都可以的 我也被弄混淆了