交流接触器如何运行维护？

在航空运输中，承运人违反强制性规定的，必须承担没有限额的完全责任。( )

阅读短文，判断正（A）误（B）。

     Len was thirty years old, and he had very long hair, He lived in a big city, but one year he did not

find any work there, so he went to a small town and began looking for work there. He went to a lot

of places, but nobody wanted him.

     Then he met an old friend, and this man said to him, "People in this town don't like long hair. Why

don't you go to a barber (理发师) ? He can cut a lot of it off and then you can get some work.."

     Len went to a barber and said, "Please cut most of my hair off." The barber began. He cut and cut

for a long time and then he said to Len , "Were you in the army a few years ago?" "Yes, I was." Len

answered. "Why did you ask that?" "Because I have found your cap," the barber answered.

( )1. Len was twenty years old.              

( )2. Len had very long hair.                

( )3. Nobody wanted Len for work.            

( )4. Len met an old classmate.              

( )5. The barber cut off a lot of Len's hair.

某有机物A是一种重要中间体．

（1）已知有机物A的相对分子质量不超过180，若将A完全燃烧，只生成CO₂和H₂O，且n（CO₂）：n（H₂O）=7：5，反应中消耗的O₂和生成的CO₂的物质的量相等，有机物A的分子式为______．

（2）根据有机物A能与NaHCO₃反应放出气体，可知A分子中含有的官能团的名称是______．

（3）有机物A分子中有四个相邻的取代基，且碳碳双键上接羟基时，或者一个碳原子上同时连接2个或2个以上羟基时不能稳定存在，又知C分子的碳环上的一氯取代物只有两种结构．则B的结构简式为______．

（4）写出下列反应的化学方程式．

①A+NaHCO₃（足量）：______．

②CD：______．

（5）C的同分异构体中，含有三个取代基的异构体共有______种，请写出其中一种的结构简式______．

建筑工程施工安全技术

施工安全技术措施是工程施工中安全生产的( )，在施工现场管理中具有安全生产法规的作用，必须认真编制和贯彻执行。

A．指导性文件

B．指令性文件

C．管理性文件

D．综合性文件

为防止细菌性痢疾流行，保护易感人群的最好方法是

A．接种疫苗
B．服用免疫球蛋白
C．少喝生水
D．服用抗菌药物
E．加强食品和饮水卫生的管理