The reason _______ matters most in his failing the English test is _______ he pays little attention to sentence structures. A. why, that B. that, that C. which, because D. what, because 答案:B
最近俄罗斯科学家利用第72号元素铪和第74号元素钨精确测定出月球至少比地球早700万年形成,铪、钨两种元素原子的本质不同是
[ ]
A.核内质子数目
B.核内中子数目
C.核外电子数目
D.相对原子质量