下图表示渗透作用装置图,其中半透膜为膀胱膜(蔗糖分子不能通过,水分子可以自由通过)。

题型:单项选择题

问题:

下图表示渗透作用装置图,其中半透膜为膀胱膜(蔗糖分子不能通过,水分子可以自由通过)。图中溶液A、B、a、b、均为蔗糖溶液,其浓度分别用MA、MB、Ma、Mb表示,且MA>MB,Ma=Mb>MA。一段时间达到平衡后,甲装置、乙装置液面上升的高度分别为h1、h2,a、b的浓度分别为M1、M2,则()

A.h1>h2 ,M1<M2

B.h1<h2, M1=M2

C.h1>h2, M1>M2

D.h1<h2 ,M1>M2

考点:高中生物物质进出细胞的方式物质进出细胞的方式题库
题型:单项选择题

在用虚位移原理求图4-118所示桁架中杆件3的内力时,将杆件3解除,代以内力S3,此时D、B两点虚位移大小δrD与δrB的关系为()。

A.A

B.B

C.C

D.D

题型:单项选择题

A “blogger” is a person who writes on an Internet computer Web site called a “blog(博客)”.The word “blog” is a short way of saying Web log, or personal Web site. Anyone can start a blog, and they can write about anything they like. There are millions of blogs on the Internet today. They provide news, information,advertisements, advice and ideas for many people who read them. They contain links to other Web sites. And they provide a place for people to write about their ideas and react to the ideas of others.

A research company called Perscus has studied more than 300 Web logs. It says that blogs are most popular with teenage girls. They use them to let their friends know what is happening in their lives. The study also says that more than 100,000 bloggers stopped taking part in the activity after a year. 

However, some people develop serious blogs to present political and other ideas. For example, the Republican and Democratic parties in the southern state of Kentucky recently started their own blogs. And American companies are beginning to use blogs to advertise their products. At the same time, some long-standing blogs have ended. Last week, blogging leader Dave Winer closed his free blog service “weblogs. com”. He says the site became too costly to continue. He started the blog four years ago. And thousands of people had written on it. They are now upset because they did not know that the site was closing. One blog that is still going strong is called Rebecca’s Pocket. Rebecca Blood created the Web-site in 1999. She wrote about the history of blogs on the site. That article led to a book called “The Weblog Handbook”. It has been translated into four languages so far. Ms. Blood says Rebecea’s Pocket gets about 30,000 visitors a month. She writes about anything and everything — politics, culture and movies. She recently provided medical advice. And she wrote about how to prevent people from stealing money from on -line bank accounts.

小题1:The author wrote this passage mainly to _________.

A.introduce an Internet computer Web site called “blog”

B.introduce a short way of saying Weblog

C.tell readers how to write blogs

D.tell readers about blogs小题2:From the passage we can learn that blogs cover almost everything EXCEPT ______.

A.account passwords

B.medical advice

C.advertisements

D.different ideas小题3:Dave Winer closed his “weblogs. Com” because __________.

A.more than 100,000 bloggers stopped taking part in the activity

B.American companies used blogs to advertise their products

C.people stole money from on -line bank accounts

D.He couldn’t afford the increasing money needed to run the blogs小题4:The reason why Rebecca’s Pocket is still going strong is that ______.

A.it was created by a woman

B.it is about the history of blogs

C.it provides useful information and advice

D.it has editions in at least four different languages小题5:What is the author’s attitude toward blog?

A.Objective

B.Sceptical

C.Disapproving.

D.Sympathetic.

题型:单项选择题

当双击某文件夹内一个PPT文档时就直接启动该PPT文档的播放模式这说明()。

A.这是PowerPoint 2010的新增功能

B.在操作系统中进行了某种设置操作

C.该文档是PPSX类型是属于放映类型文档

D.以上说法都对

题型:单项选择题

闭合导线观测转折角一般观测()。

A、左角

B、右角

C、外角

D、内角

题型:单项选择题

按照布朗斯特酸碱理论水中重碳酸根是()。

A.碱性物质

B.酸性物质

C.中性物质

D.两性物质

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