on the knocker informal 非正式

(Brit.)going from door to door canvassing, buying, or selling

(英)挨家挨戶地盤查（收購，賣貨）

(Austral./NZ)(of payment) immediately; on demand

(澳／新西蘭)（支付）立即；在要求時(shí)

he has to pay cash on the knocker.

他必須立即支付現(xiàn)金。