某有机物A由C、H、O三种元素组成,相对分子质量为90。将9.0 g A 完全燃烧的产物依次通过足量的浓硫酸和碱石灰,分别增重5.4 g和13.2 g。A能与NaHCO3溶液发生反应,且2分子A之间脱水可生成六元环化合物。有关A的说法正确的是A.分子式是C3H8O3 B.A催化氧化的产物能发生银镜反应C.0.1 mol A与足量Na反应产生2.24 L H2(标准状况)D.A在一定条件下发生缩聚反应的产物是 H [ OCH2CH2CO ] nOH
I’m sure that your letter will get______ attention. They know you’re waiting for the reply.
All the dishes in this menu, ______ otherwise stated, will serve two to three people.
The children loved their day trip, and they enjoyed the horse ride ______.
Progress______ so far very good and we are sure that the work will be finished on time.
Charles was alone at home, with_______ looking after him.