Currency relative values of the different currencies. Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance. Other definitions of the term "currency" are discussed in their respective synonymous articles banknote, coin, and money. The latter definition, pertaining to the currency systems of nations, is the topic of this article. Currencies can be classified into two monetary systems: fiat money and commodity money, depending on what guarantees the value (the economy at large vs. the government's physical metal reserves). Some currencies are legal tender in certain political jurisdictions. Others are simply traded for their economic
Shall and will it is nearly absent from ordinary speech. The legal reference "Words and Phrases" dedicates 76 pages to summarizing hundreds of lawsuits that centered around the meaning of the word shall. When referencing a legal or technical requirement, "Words and Phrases" instead favors "must" while reserving "should" for recommendations. As noted above, "should" and "would" originated as the preterite (past tense) forms of "shall" and "will". In some of their uses they can still be identified as past (or conditional) forms of those verbs, but they have also developed some specific meanings of their own. The main use of "should" in