3He可以作为核聚变材料,以下关于3He的说法正确的是( )
A.比4He少一个质子
B.与4He互为同位素
C.与4He都是氦元素的同素异形体
D.比4He多一个中子
答案:B
Chinese government should ______ taking action at once to defend the Diaoyu Islands.
A.set about
B.set off
C.set out
D.set down
卤水依其色泽分为红卤水、白卤水和盐水卤三类。( )