AP microeconomics is an elective course offered by College Board of the United States in senior high schools. It aims to help high school students successfully apply to universities and enter their chosen majors. The course is as difficult as a freshman course in an American University. Microeconomics belongs to the category of social science. It studies how individuals and enterprises make decisions and how to interact in the market. Economics is an elective course offered by many universities in the United States. It is also a required course for business and economics majors. The course generally lasts for two semesters. The test is in every May. The courses and examinations are all in English, and the requirements for English proficiency are high.