题目: M={x|y=x2-1},N={y|y=x2-1,x∈R}那么M∩N=( )A.∅B.MC.ND.R 答案: M={x|y=x2-1}=RN={y|y=x2-1,x∈R}=[-1,+∞)∴M∩N=R∩[-1,+∞)=[-1,+∞)=N故选C.
题型:问答题 In relation to the formation of companies:(b) State and explain the individuals and entities that are prohibited from forming new companies. (5 marks) 查看答案
题型:单项选择题 男,15岁,因右下颌6急性根尖周炎进行根管治疗,在根管预备后,选择5%次氯酸钠、3%H2O2交替冲洗根管,选择该组冲洗液的原因如下,除了()A.能溶解根管壁牙本质B.能产生新生氧C.有充分发泡作用能使根管内碎屑朝着牙冠方向排出D.有很强的杀菌作用E.对坏死组织有溶解作用 查看答案