A currency union is when two or more economies (usually sovereign countries) share a common currency or mutually decide to peg their exchange rates to the same reference currency to keep the value of their monies similar. There are more than 20 official currency unions, the largest of which is the euro, which is used by 19 of the 28 members of the European Union.
Besides European Union, do you know there is another currency union in Caribbean area? The Eastern Caribbean Currency Union (ECCU) is a development of the Organization of Eastern Caribbean States. The Eastern Caribbean Dollar is the official currency for Anguilla, Antigua and Barbuda, Dominica, Grenada, Montserrat, Saint Kitts and Nevis, Saint Lucia, and Saint Vincent and the Grenadines.
Do you know how to say the name of these countries in Chinese?