稳态噪声比脉冲噪声对人体听力影响大。（）

某市对2400名年满15岁的男生的身高进行了测量，结果身高（单位：m）在1.68～1.70这一小组的频率是0.25，则该组的人数为______．

下列说法，符合地理环境整体性的是　　　 　　（　　）

A．当草原植被为森林植被所取代时，可能使温室效应增强

B．当森林减少或人为清除大量森林植被时，可能使温室效应减弱

C．植被类型的改变，可能引起地表水热交换发生变化

D．森林的减少，可能引起气温日较差减小

甲物体以5 m/s的速度做匀速直线运动，乙物体以5 m/s的平均速度做变速直线运动。在下列说法中不正确的是[ ]

A．甲每秒内一定通过5 m 的路程

B．乙每秒内不一定通过5 m 的路程

C．因为甲、乙的速度值都是5m/s，所以它们运动的快慢程度是一样

D．虽然甲、乙的速度值都是5m/s，但它们运动的快慢程度却不一样

NEW YORK---One in five U.S. workers regularly attends after-work drinks with coworkers, where the most common mishaps range from badmouthing another worker to drinking too much, according to a study released on Tuesday.

Most workers attend so-called happy hours to bond with colleagues, although 15 percent go to hear the latest office gossip and 13 percent go because they feel necessary, said the survey conducted for CareerBuilder. com, an online job site. As to what happens when the after-work drinks flow, 16 percent reported bad-mouthing a colleague, 10 percent shared a secret about a colleague and 8 percent said they drank too much and acted unprofessionally. Five percent said they had shared a secret about the company, and 4 percent confessed to singing karaoke. While 21 percent of those who attended said happy hours were good for networking, 85 percent said attending had not helped them get closer to someone higher up or get a better position. An equal number of men and women said they attended happy hours with co-workers, with younger workers aged 25 to 34 most likely and workers over 55 least likely to attend. Overall, 21 percent of workers attend happy hours with co-workers and; of those nearly a quarter go at least once a month.

The survey was conducted online by Harris Interactive on behalf of CareerBuilder. com among 6,987 full-time employees between February 11 and March 13. Harris Interactive said the results had a sampling error of plus or minus 1.2 percentage points.

56. Harris Interactive made the survey to find out            .

A. how U.S. workers spend their after-work time        

B. what U.S. workers do at after-work drinks

C. the relationships between U.S. workers        

D. who are most likely to attend after-work drinks

57.         of workers who attend after-work drinks speak ill of a colleague. 

A. 4 percent       B. 8 percent     C. 16 percent     D. 10 percent

58. According to the passage, most of those surveyed believed attending after-work drinks             .

A.benefited them a lot                B. could provide information  

C.only made them relaxed            D. was of no help to them

59. We can learn from the text that                 .

A. workers over 55 don’t like to attend happy hours at all

B. about 75% of  workers go more than once a month  

C. 10.5% of male workers attend happy hours with co-workers

D. about 700 workers surveyed shared a secret about a co-worker

60. After the survey, it can be inferred that                    .

A. all the workers oppose after-work drinks

B. the workers may change their attitudes towards after-work drinks  

C. all the workers support after-work drinks

D. all the workers are suggested going to attend after-work drinks

根据以下信息，回答第271题至第272题。

在使用经济订货批量的情况下(假设需求是常量)，最优的订货量是2500单位，安全存货是500单位，订货前置期为5天。年存货储存成本等于平均存货水平的25%。公司以每单位5美元采购产品，以8美元的价格销售出去。另外，每次订货花费150美元，月需求量为4000单位。

年存货储存成本为（）。

A．850美元

B．1250美元

C．1750美元

D．2250美元