You know, this isn't really my area of expertise , but I know a few great resources. Let me write them down for you.
这我还真不在行，要不，我知道资料会对你有帮助，我帮你写下来，你可以去查一下。If you are not not good at making investments, talk to a financial consultant and entrust your savings with him.
假如你对投入资金不在行，没出国疑问找个理财顾问，委托他帮你投入资金。if you are not good at makings , talk to a financial consultant and entrust your savings with him.
如果你对投资不在行，可以找个理财顾问，委托他帮你投资。In school, the only thing I totally flunked out in was understanding girls.
在学校，我唯一不在行的就是了解女孩子，这方面我完全不及格。In school, the only thing I totally fluncked out in was understanding girls.
在学校，我唯一完全不在行的就是了解女孩子。I'm no expert, but i believe in the context of a luncheon invitation, you might want to skip the reference to bowel movements.
这方面我不在行不过我相信如果是邀请别人吃午餐，你最好不要说些肠运动的事。Obama is a powerful speaker, but he is not at his best when he's reading something written by someone else.
奥巴马是个强有力的演说家，但是他对读别人写作的东西却不在行。He usually persuades his daughter to book his flights online as he says he is not a computer buff.
他常常让自己的女儿帮他在线预订航班，因为他说自己对电脑不在行。She was a bad cook and could do little more than chops and steaks .
她做饭很不在行，而且所能做的也不过是排骨和牛排而已。