压缩机开机后，什么原因会使油压突然降低（＜0.1Mpa）？

请示的主要特点包括下列哪些？（）

A.沟通性、双向性、陈述性

B.单一性、期复性、紧迫性

C.单向性、陈述性、沟通性

D.全面性、双向性、沟通性

某种手液中含有PCMX，对革兰氏阳性和阴性菌及霉菌具有极好的杀灭效果。

（1）PCMX分子中含有苯环，相对分子质量为156.5，该有机物含有碳、氢、氧、氯四种元素，其中氯和氧元素的质量比为35.5︰16，则有机物的分子式是_______。

（2）PCMX分子的苯环上含有四个取代基，其中相同的两个取代基处于间位，另外两个不同的取代基处于对位；该有机物在一定条件下能跟浓溴水发生苯环上的取代反应，且PCMX与的物质的量之比为1︰2。PCMX结构简式是_________________，其中含氧官能团名称是__________________。

（3）PCMX在光照的条件下，跟氯气反应生成一氯代物的化学方程式是_____________________________________________。

（4）已知

____________________________________________________________________

（5）PCMX的同分异构体中，有两个取代基，且能跟溶液发生显色反应的有________种，写出其中两种的结构简式________________，_________________。

阅读理解。

     Ed Viesturs grew up in Rockford, Illinois, where the tallest thing on the horizon was the water tower.

But on Thursday, Viesturs became the only American to climb to the top of the world's 14 highest mountains.

     His last hike was up Mount Annapurna, in Asia's snowcapped Himalayas. At 26,545 feet, its peak is the

10th highest in the world. It is the mountain that inspired him to start climbing.

     "It tends to be the trickiest, the most dangerous," said Viesturs. "There's no simple way to climb it. There

are threatening avalanches (雪崩) and ice falls that protect the mountain."

     In high school, Viesturs read French climber Maurice Herzog's tale of climbing the icy Annapurna. Herzog's

story was of frostbite (冻伤) and difficulty and near-death experiences. Viesturs was hooked right away.

     Viesturs got his start on Washington's Mount Rainier in 1977, guiding hikes in the summer. Fifteen years

ago, he set out to walk up to the world's highest peaks. Finally, he's done.

     The pioneering climber talks about mountains as if they were living creatures that should be treated with

respect. "You have to use all of your senses, all of your abilities to see if the mountain will let you climb it,"

said Viesturs. "If we have the patience and the respect, and if we're here at the right time, under the right

circumstances, they allow us to go up, and allow us to come down."

     What's next for a man who can't stop climbing? "I'm going to hug my wife and kids and kind of kick back

and enjoy the summer," says Viesturs. But for a man who's climbed the world's 14 tallest mountains, he will

probably soon set off on yet another adventure.

1. What record has Ed Viesturs set? [ ]

A. He has succeeded in climbing to the world's 14th highest mountain.

B. He has been to the top of the world's 14 highest mountains.

C. He has become the first to climb to the height of 26,545feet.

D. He has become the first man to climb to the top of 14 highest mountains in the world.

2. The underlined word "hooked" in Paragraph 4 can be replaced by "_____". [ ]

A. frightened

B. discouraged

C. interested

D. upset

3. The author used Viestures' words in Paragraph 6 to support a view that _____. [ ]

A. mountain climbing is a dangerous sport

B. mountains should be regarded as living creatures

C. mountain climbing needs more skills than physical energy

D. those who like mountain climbing won't stop climbing

4. What's the next probably plan of Viestures? [ ]

A. Stopping climbing and staying with his family.

B. Climbing to the top of the world's 14 tallest mountains again.

C. Climbing another one of the highest mountains.

D. Writing down the experiences about his adventure.

以下三个小题基于“学生选课课程”数据库中的如下三个关系：学生基本信息：S（S#，SNAME，SEX，AGE） 选课信息：SC（S#，C#，GRADE） 课程信息：C（C#，CNAME，TEACHER）

若要求“查询选修了3门以上课程的学生的学生号”，正确的SQL语句是

A．SELECT S# FROM SC GROUP BY S# WHERE COUNT（*）> 3

B．SELECT S# FROM SC GROUP BY S# HAVING COUNT（*）> 3

C．SELECT S# FROM SC ORDER BY S# WHERE COUNT（*）> 3

D．SELECT S# FROM SC ORDER BY S# HAVING COUNT（*）> 3

职工在作业过程中，应当严格遵守安全生产规章制度。