[经] average age of receivable

yīng shōu zhàng kuǎn píng jūn zhàng líng ㄧㄥ ㄕㄡ ㄓㄤˋ ㄎㄨㄢˇ ㄆㄧㄥˊ ㄐㄩㄣ ㄓㄤˋ ㄌㄧㄥˊ