题干
Yesterday I ________ an old college friend in the restaurant, who was still very ________ about what he ate.
A：came across; worried
B：bumped into; particular
C：knocked into; complained
D：ran into; curiou
答案(点此获取答案解析）
B
物与足量水反应，在标准状况下得到672mL混合气体，将混合气体电火花点燃，恰好完全反应，则原混合物中钠、氧化钠、过氧化钠的物质的量之比为
