Why not use something big?

Don't use big things. It means that everything is full today, and one more point will pass, so it is not appropriate to do things. Don't do anything important on this day

This sentence comes from the Yellow Calendar, which is based on the China lunar calendar and has a perpetual calendar of good and bad luck every day. According to legend, the yellow calendar was created by Xuanyuan Huangdi, so it is called the yellow calendar. The main content of the Gregorian calendar is the 24 solar terms, as well as daily taboos, branches, values, stars, moon phases, good or bad luck and so on.

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