knocker
英 ['nɒkə]
美['nɑkɚ]
- n. 门环；敲击者；吹毛求疵的人
词组搭配
on the knocker informal 非正式
(Brit.)going from door to door canvassing, buying, or selling
(英)挨家挨户地盘查（收购，卖货）
(Austral./NZ)(of payment) immediately; on demand
(澳／新西兰)（支付）立即；在要求时
he has to pay cash on the knocker.
他必须立即支付现金。