单项选择题
A．a bank is closed for one or more days B．too many depositors try to draw out their money at one time C．there is not enough money to pay all its depositors at one time D．tellers of a bank take their own money from the bank
A．Bartered goods. B．Fiat money. C．Coin currency. D．Intangible forms.
A．the life experience of great men B．the movement of the stars and the planets C．the scientific study of natural objects in space D．the theories developed by scientists of old times