自我复制能力最强的细胞是（） A.网织红细胞 B.定向祖细胞 C.前体细胞 D.造血

引起膀胱 * * 瘘的主要因素为（）。

A.放射治疗宫颈癌

B.第二产程延长组织挤压而缺血坏死

C.妇科手术损伤

D.长期便秘

E.子宫托安放不当

中国经济网载文指出，当前，要把扩大就业摆在经济社会发展更加突出位置，坚持实施积极的就业政策，千方百计增加就业岗位。要实现这一要求.就应

A．确立国有经济为主体的基本经济制度

B．建立劳动者自主择业为主的就业机制

C．逐步建立有利于扩大就业的经济结构和增长模式

D．建立健全与经济发展水平相适应的社会保障体系

为使发送方不能否认自己发出的签名消息，应该使用以下哪种技术

A．数据加密

B．数字签名

C．防火墙

D．链路加密

湿鼠曲草功效与作用

Visitors to Britain may find the best place to sample local culture is in a traditional pub. But these friendly hostelries can be minefields of potential gaffes for the uninitiated.
An anthropologist and a team of researchers have (1) some of the arcane rituals of British pubs—starting with the (2) of getting a drink. Most pubs have no waiters—you (3) to go to the bar to buy drinks. A group of Italian youths (4) for 45 minutes before they realized they would have to (5) for their own. This may sound inconvenient, but there is a (6) purpose.
Pub culture is designed to (7) sociability in a society known for its reserve. Standing at the (8) for service allows you to chat with others (9) to be served. The bar counter is possibly the only (10) in the British Isles in which friendly conversation with (11) is considered entirely appropriate and really quite normal (12) . "If you haven’t been to a pub, you (13) been to Britain." This tip can be found in a (14) , Passport to the Pub: The Tourists’ Guide to Pub Etiquette, a (15) code of conduct for those wanting to sample "a central part of (16) life and culture". The trouble is that if you do not (17) the local rules, the experience may fall flat. For (18) , if you are in a big group, it is best if only one (19) two people go to buy the drinks. Nothing irritates the (20) customers and bar staff more than a gang of strangers blocking all access to the bar while they chat and dither about what to order.