A:K2CO3
B:CO(NH2)2
C:KNO3
D:Ca(H2PO4)2
复数52i-1的共轭复数是( )
Broadway has been well-known for its theatres since the early ____ century. (twenty)
①小丽期中考试成绩和上学期相比有了很大的退步
②小明竞选班委失利
③书法竞赛小红没有取得好名次
④小刚顺利通过合唱团的选拔