交换

exchange;swap
两国的战俘～遇到了麻烦，双方在～时减少了实际～的数量。The prisoner swap between the two countries ran into trouble. Both reduced the number swapped at the exchange./劳务～exchange of services/等价～exchange of equal value/～照会（换文）exchange of notes/～批准书exchange of ratification/～意见exchange views;compare notes/～场地change of courts,goals or ends /～商品exchange of commodities/～价值exchange value/～文本exchange of texts (or copies)/～照片exchange of photos