若单项式﹣3am﹣4b3与b|n﹣1|a3是同类项,则mn=[ ]
A.28
B.﹣14
C.28或﹣14
D.以上都不对
答案:C
I first met Li Ming at a friend birthday party five years ago. Then I invited Li Ming over in my place. We listen to my CDs together and soon became best friend. Three years ago, Li Ming’s parents invited I to spend two wonderful week in Qingdao with them during the summer holiday. Li Ming and I loved walking along the beautifully beaches there. Last year I was ill but had to stay in hospital for a week. Li Ming came see me every day. Then his father has changed jobs and they moved to another city. Since then we haven’t see each other much. But we’ve kept writing to each other.
颌顶位又称为()
A.顶颌位
B.下上轴位
C.上下轴位
D.额鼻位
E.后前位