下列各组物质的俗名、化学名称和化学式表示同一种物质的是( ) A.银、汞、Hg

题型:选择题

问题:

下列各组物质的俗名、化学名称和化学式表示同一种物质的是(  )

A.银、汞、Hg

B.干冰、水、H2O

C.熟石灰、氧化钙、CaO

D.纯碱、碳酸钠、Na2CO3

考点:化学式的写法和意义
题型:选择题

汽车由静止开始做匀加速直线运动,速度达到v的过程中的平均速度为v1;若汽车由静止开始以额定功率行驶,速度达到v的过程中的平均速度为v2,则[ ]

A.v1=v2

B.v1<v2

C.v1>v2

D.条件不足,无法判断

题型:选择题
在寻找熔丝熔断的原因中,下列原因中可以排除的是(  )

A.插座内部“碰线”

B.插头内部“碰线”

C.灯座内部“碰线”

D.开关内部“碰线”

题型:选择题

向某溶液中滴入无色酚酞试液后不显色,向该溶液中滴入紫色石蕊试液则(  )

A.一定显红色

B.可能紫色

C.一定显无色

D.可能紫色也可能显红色

题型:选择题

阅读理解

     Last year college students in America spent an estimated $700 on textbooks on average. The

National Association of College Stores reported more than five billion dollars in sales of textbooks

and course materials.

    The association spokesman Charles Schmidt says electronic textbooks now just make up

2%~3% of sales. But he says that is expected to reach 10%~15% by 2012.

      Online versions(版本) are now available for many of the most popular college textbooks. An

etextbook can cost half the price of a new print textbook.But students usually lose access to them

after the end of the term.And the books cannot be placed on more than one device(设备), so they

are not easy to share.

     So what do students think of etextbooks?Administrators at Northwest Missouri State University

wanted to find it out.Earlier this year they tested them with 500 students in 20 classes.

    The university is unusual.It provides laptop computers for all 7,000 of its fulltime students.It does

not require students to buy their textbooks either.They rent them to save money.The school aims to

save even more by moving to etextbooks.

     The students in the survey reported that downloading the books from the Internet was easy.They

liked the idea of carrying lighter backpacks.And 56% said they were better able to find information.

     But most found that using etextbooks did not change their study habits.And 60% felt they read

more when they were reading on paper.In all, almost half the students said they still liked physical

textbooks better.

     But the survey found that cost could be a big influence.55% said they would choose etextbooks

if using them meant their textbook rental fee would not increase.

     Roger Von Holzen heads the Center for Information Technology in Education at Northwest

Missouri State University.He tells us that administrators are disappointed with the etextbooks now

available because the majority are not interactive(交互式的).

     He thinks growth will come when more digital books include video, activities, games and other

ways to interact with the information.The technology is improving.But for now, most of the books

are just words on a screen.

1. Etextbooks are not better than paper books in that________.

A. they cost more money              

B. they're difficult to carry

C. they're not convenient to share        

D. they can't be downloaded from the Internet

2. How many surveyed students think paper books make better reading?

A. 60%.

B. 56%.

C. 55%.

D. 50%.

3. It can be inferred from the text that in the future________.

A. digital books will be more popular      

B. the digital books available need improvement

C. free digital books are available online      

D. digital books will replace print textbooks

题型:选择题

某制造厂生产甲、乙两种产品,有关资料如下:
(1)甲、乙两种产品2008年1月份的有关成本资料如下表所示:
                                             单位:元

产品名称 产量(件) 直接材料单位产品成本 直接人工单位产品成本
100 50 40
200 80 30
(2)月初甲产品在产品制造费用(作业成本)为3600元,乙产品在产品制造费用(作业成本)为4600元;月末在产品数量,甲为40件,乙为60件,总体完工率均为50%;按照约当产量法在完工产品和在产品之间分配制造费用(作业成本),本月发生的制造费用(作业成本)总额为50000元,相关的作业有4个,有关资料如下表所示:
作业名称 成本动因 作业成本(元) 甲耗用作业量 乙耗用作业量
质量检验 检验次数 4000 5 15
订单处理 生产订单份数 4000 30 10
机器运行 机器小时数 40000 200 800
设备调整准备 调整准备次数 2000 6 4
要求:

假设决策者计划让单位售价高于单位成本10元,根据第(2)问的结果确定甲和乙的销售单价,试分析可能造成的不利影响。

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