And how is it known that Mars had hafnium - 187 ?那么是如何知道火星有铪 -187 的 呢 ?This activator is acyl amine - the hafnium activator that ether is a foundation.该催化剂为酰胺 - 醚为基础的铪催化剂.Chemical form of hafnium is perchlorate or nitrat...
The persons elected will sit till 31 Dec . , 1973.当选者任期至1973年12月31日.The effective date of this contract will begin from Dec . 30 th, 2007.这个合同的有效期将从2007年12月30日开始.On the evening of Dec. 31, we usually celebrate the New Ye...