But at the same time, under the law... and the laws says that the Federal Reserve notes are legal tender and everybody has to obey all he laws doing it, because a Federal Reserve note is a dollar.

不过与此同时，根据法律……法律却说联邦储备银行券是法定货币并且所有人必须服从法律，因为根据法律，联邦储备银行券就是美元。

youdao

The notes and coins of the 12 national currencies ceased to be legal tender by the last day of February, although most banks would continue to exchange the currency notes for several years.

这12国原有的纸币和硬币到2月底就已经不再是合法的支付手段，但大多数银行将继续兑换数年。

youdao

This is so because legal tender laws allow debtors to effectively abrogate private currency debt contracts at will by offering Federal Reserve notes in lieu of what was specified.

FORBES: Private Currency Competition Is The Monetary Answer