题干
---Look! Some people are running the red lights.
---We should wait others are breaking the rule.
A：although
B：if
C：unless
D：because
答案(点此获取答案解析）
A
---Look! Some people are running the red lights.
---We should wait others are breaking the rule.
A：although
B：if
C：unless
D：because
已知 X＋、 Y2＋、 Z－、 W2－四种离子均具有相同的电子层结构。下列关于 X、Y、Z、W 四种元素的描述，正确的是（ ）
