【单选题】设关系R和S的属性个数分别为n和m,那么R×S操作结果的属性个数为:
【判断题】If a transaction is concluded under trade terms in C group, the seller shall pay the freight to ship the goods to the destination, but shall not be responsible for the risk of goods in transit.
【判断题】If a transaction is concluded under trade terms in C group, the seller shall pay the freight to ship the goods to the destination, but shall not be responsible for the risk of the goods in transit.
【单选题】感官在接受不同刺激时会产生感觉的对比现象,这叫做()
【单选题】( )是指同一感觉器官在接受不同刺激时会产生感觉的对比现象。
【多选题】签定就业协议后,尚未派遣的,下列哪种情况可以不视为违约?