According to the definition of Lu Hefa (2005:22), the public sign has four application signaling functions in practical applications, namely indicative, informative, restrictive and mandatory.
According to the definition of Lu Hefa (2005:22), the public signs in practice should be used in 4 kinds of "should be used" to show the function, that is, the indication, indication, restriction and mandatory.
According to the definition of LV Hefa (2005:22), public signs have four application functions in practical application, namely indicative, suggestive, restrictive and mandatory.<br>