[经] declining-unit-use charge method
dān wèi shǐ yòng dì jiǎn chū zhàng fǎ ㄉㄢ ㄨㄟˋ ㄕˇ ㄩㄥˋ ㄉㄧˋ ㄐㄧㄢˇ ㄔㄨ ㄓㄤˋ ㄈㄚˇ