National debt: a financial adjustment tool issued by the state in the form of fiscal deficit and financed by the public for large-scale national projects or special purposes.

Fund: issued by professional fund companies, absorbing social idle funds, operated by specialized personnel, engaged in financial management tools in financial markets such as stocks and futures.

Stock: issued by the company, used to absorb social idle funds, unlimited repayment of principal and interest, * * * a kind of ownership certificate tool separated from the rights and obligations of the company.

Foreign exchange: a tool to adjust the purchasing power of currencies in different countries because of their different situations.

Futures: short for buying and selling uncertain commodities at a certain time in the future by using the principle of currency leverage.

Spot: as opposed to futures.

I don't know if it's right, but I'll understand it slowly.