【简答题】化合物 A 能溶于水,但不溶于乙醚,元素分析含 C、 H 、 O 、 N 。 A 加热失去一份子水得化合物 B 。 B 与氢氧化钠的水溶液共热,放出一种有气味的气体。残余物酸化后得一不含氮的酸性物质 C 。 C 与氢氧化铝锂反应的产物用浓硫酸处理,得一气体烯烃 D ,其分子量为 56 。该烯烃经臭氧化再还原水解后,分解得一个醛和一个酮。 试 推测 A ~ D 的结构式
【简答题】小题1:If you take some ___________ after supper, you will be thinner. (exercise ) 小题2:I have a good ___________ habit, so I’m very healthy. ( eat ) 小题3:They have been to many ______________ countries....
【简答题】试计算积分 ∫C(|z|—ezsin z)dz 之值,其中C为圆周|z|=a>0.
【简答题】Exercise
2: Directions: you will hear eight short conversations. After each
conversation, a question will be asked. Answer the questions. 1.
How much are two bags?
【简答题】用所给词的适当形式填空 1. If you take some __________ after supper, you will be thinner.(exercise) 2. I have a good __________ habit, so I'm very healthy.(eat) 3. They have been to many __________ countries.(wes...
【单选题】()督促本企业相关部门履行药品不良反应的监测和报告。