In the 1970s and 1980s counter trade was different from the old

In the 1970s and 1980s counter trade was different from the old practice although some similarities remained. Current counter trade partners are not necessarily familiar partners and goods exchanged are sometimes vertically related. Current counter trade can be categorized as follows.
【正确答案】：20世纪70年代和80年代的对销贸易虽保留历来某些相同点但已不同于以往的做法贸易双方并不一定互相熟悉,交换的产品为纵向有联系的货物当今对N销贸易分为以下几种。