【单选题】已知全集U={1,2,3,4,5},集合A={3,4},B={2,3,5},那么集合A∪(C ∪ B)等于( )
【判断题】Collins 试剂是指 铬酸吡啶盐 ( )。
【判断题】Collins 试剂是指 氯铬酸吡啶鎓盐 ( )。
【单选题】已知全集U={1,2,3,4,5},A={1,3},B={3,5},则
【单选题】现实主义和自由主义都认为国家是理性的,两者
【单选题】已知全集U={1,2,3,4,5},集合A={1,3},B={3,4,5},则集合C U (A∩B)=( )
【判断题】Collins 试剂是指 铬酐吡啶配合物 ( )。
【单选题】He told us ________ sad and that it would be better for everyone.
【简答题】Once my father and I went to see a circus(马戏 ). A family was standing in front of us for tickets. The family had eight children. Their clothes were not but they were clean. They were talking about the...
【单选题】He told us not ________ sad, and that it would be better for everyone to keep calm.