制备碘溶液时加入碘化钾的作用是A．增溶B．补钾C．助溶D．增加离子强度E．防止碘挥发

风险的发生是一种随机现象，但从总体上看它又具有规律性。风险的（）便是风险总体上的必然性与个体上的偶然性统一的结果。

A.发展性

B.社会性

C.普遍性

D.不确定性

Tara、Claudia、Monica、Terry 和Tony正在挑选自己所需要的网站。第56至60题是他们的个人情况介绍。阅读下面六个网站的简介(A、B、C、D、E、F)，选出符合各人需要的最佳选项，选项中有一项是多余选项。

56. Tara has got a new video camera and is crazy about it. Wherever she goes, she’d like to take it with her and record everything she finds interesting. She thinks it cool to share her life with others through the recordings.

57. As a newcomer to this city, Claudia wants to make new friends with people around her. She likes this city except for one thing, that is, she is not allowed to raise any pet due to the flat rules. That’s too much for an animal lover like her.

58. Monica is clever with her hands and likes making toys. She wants to find a way to show her work to others and share the pleasure with them. If possible, she’d like to make pocket money by selling the toys.

59. Terry worries about his phone bill every month. As he has lots of friends, making phone calls, sending and receiving messages are a necessary part of his life. Sometimes he has to say hello to each of his friends by mobile phone. It costs him lots of time and money.

60. In his spare time, Tony travels a lot. It’s hard for his friends to get in touch with him when he’s away. He’d like to find a way to share his travel experiences with his friends and let them know where he is.

------------------------------------------------------------------------------------------------------

A. www.ddff.com

The site enables users to keep track of where their friends are and get informed of who is visiting their hometown. Users put in their travel plan and link to their friends. It allows them to see where everyone is.

B. www.euke.com

A New York-based Internet businessman once said it was “your place to buy and sell all things handmade”. You can sell everything made by yourself from clothes and furniture to music on Euke.com. The site was founded in 2005 and now has more than half a million users and 60,000 sellers.

C. www.momo.com

Created by a London games firm, Momo combines computer pet games with social communication and questions. Players keep “pets”, and look after them by answering regular questions. “Pets” can play with each other online, providing “pet owners” with chances to socialize. With its funny pictures and attractive qualities, Momo wants to become the next craze for young people.

D. www.png.canwest.com

The site provides a platform for companies and individuals that try to satisfy every need of today’s customers. The practice has moved from the office to the customer’s kitchen and beyond. And the services provided include everything from dog walking to laundry. Founded this year, the site already has more than 5,000 users.

E. www.cosm.com

Instead of marketing videos, Cosm centers on online video diaries. The site has not gone public yet, but has had positive reviews from testers. The website’s founder was once an Internet advisor to an international company.

F. www.ttter.com

Ttter enables you to text messages to large groups of people at a time, and for free. Sign up and send it a message, from a phone or the Internet, and it will be sent to receivers. The message is limited to just 140 characters. Set up in March, 2006, Ttter.com has already attracted over 500,000 users.

257，178，259，173，261，168，263，( )

A．163
B．164
C．178
D．275

科学家常用哺乳动物红细胞作材料研究细胞膜的组成，是因为（）

A.哺乳动物红细胞的细胞膜在光学显微镜下容易观察到

B.哺乳动物红细胞容易得到

C.哺乳动物红细胞在水中容易涨破

D.哺乳动物成熟的红细胞内没有核膜、线粒体膜等膜结构

（）的概念是指协调者为了达到解决问题的目的，在协调过程中，利用或者依靠一切外在条件。

A、刚性协调

B、借权用力

C、权势力

D、舆论力