A wide range of factors interact to determine the exchange rate level: the government, market forces of supply and demand for a particular country's currency, interest rates, inflation, a country's balance of trade and/or payments, and consumers' expectations about what will happen in the future.
Use quotation marks for direct quotes. Use quotation marks to surround direct quotes from a source, person, article, or other source. Use a comma before a quote only if you precede the quote with an identifier (a tag) such as he said or According to experts..
Double Quotation Marks for Words Used as Examples. Double quotation marks can also be used when you are writing a sentence and you want to refer to a word rather than use its meaning. Since I talk about words a lot, this comes up in almost every Grammar Girl episode. It's a style choice.