Simplify the following text for a Grade 9 native English-speaking person.
Original: In most of East Asia today , the Gregorian calendar is used for day-to-day activities , but the Chinese calendar is still used for marking traditional East Asian holidays such as the Chinese New Year ( the Spring Festival ) , the Duan Wu festival , and the Mid-Autumn Festival , and in astrology , such as choosing the most auspicious date for a wedding or the opening of a building .
Simplified: Today in China the Gregorian calendar is used for most activities . The Chinese calendar is still used for traditional Chinese holidays like Chinese New Year , Duan Wu festival , and the Mid-Autumn Festival .