Economics: The main courses are western economics (micro and macro) and the history of western economics. I can work in a bank after graduation.
Finance: There are specialized financial courses. When I was in college, I talked about the interaction between government departments, enterprises and consumers and the increase and decrease of social welfare. The rest of the courses also include economics courses.
Finance: there are western economics, international finance, financial practice (how the financial system of banks works) and so on.
Investment: I'm not sure, but there must be international finance, because it is about hedging and futures.
International Trade: Hehe, my major is finance and economics, and there is an international trade practice, which is the most important one. Besides, I have passed Band 6.
I hope you can understand. . . . . . .