A:stopped; were still looking
B:will stop ;are still looking
C:have stopped ; were still looking
D:stop ; will have looked
我班来了一位新学生,他在自我介绍时说自己的姓和我国历史上最早的朝代名称相同,这位新同学姓( )
用元素符号或化学式填空:
(1)3个氮分子 ____
(2)4个硫离子 ____
(3)n个铜原子 ____
(4)正五价的磷元素 ____