[经] specialization of commodities and duty rates

shāng pǐn yǔ shuì lǜ de míng xì fēn lèi ㄕㄤ ㄆㄧㄣˇ ㄩˇ ㄕㄨㄟˋ lv4 ㄉㄜ˙ ㄇㄧㄥˊ ㄒㄧˋ ㄈㄣ ㄌㄟˋ