<human>:  What are the time zones of different countries?
<bot>: The time zones of different countries vary depending on their location. For example, in the United States, the time zones include Pacific Standard Time (PST), Mountain Standard Time (MST), Central Standard Time (CST) and Eastern Standard Time (EST). In Canada, there are Pacific Standard Time (PST), Mountain Standard Time (MST), Central Standard Time (CST), Eastern Standard Time (EST) and Atlantic Standard Time (AST). In Europe, the main time zones are Greenwich Mean Time (GMT), Central European Time (CET) and Eastern European Time (EET). In Australia, the main time zones are Australian Eastern Standard Time (AEST) and Australian Western Standard Time (AWST).