对于原发淋巴瘤描述不正确的是A．幕上多见 B．均边界清楚 C．周围水肿明显 D．对放

下列做法中错误的是（　　）

A．点燃可燃性气体之前必须验纯

B．给玻璃仪器加热时都要垫石棉网

C．做实验的废液倒入指定容器内

D．在实验药品贮藏室门口写上“严禁烟火”

传统计划经济时期乡村社区治理的基本策略是什么？

截止到2008年，中国的网络规模容量及用户数都居世界第一。人们通过网络获取他们感兴趣的各种信息，借助网络丰富的内容填充自己的生活。据此回答下题。

目前网上购物还存在一些问题，政府应该在网络交易方面有所作为。下列属于政府应采取的措施有 

①通过立法，规范网上交易秩序

②加快建设社会信用体系

③打击网上交易中的诈骗等违法犯罪活动

④要求银行大力发展信用卡业务  

A．②③

B．①④

C．①②③

D．①②③④

Today I’d like to talk about how to become a (1) . Usually you have to start at the beginning. That is, you have to begin (2) of some sort on a local newspaper, a (3) , maybe on a small magazine -- work (4) . Now there aren’t that many organizations which have large numbers of foreign correspondents so you also have to (5) with that aim (6) . Another way of doing it is to work abroad, and work as (7) . That’s somebody who sells stories, and gets paid (8) , to newspapers and magazines and so on. And hoping to (9) that way, and eventually to be offered a (10) .
I don’t really know (11) are needed, but obviously a degree in modern languages or (12) would be very useful. But, a degree in itself probably wouldn’t (13) . It wouldn’t be enough to get you job. It wouldn’t (14) to make an editor decide to (15) . So it’s difficult to define the (16) . You’re going to need (17) and the ability to assimilate information (18) and then produce stories which (19) of the newspaper or radio or television station you (20) .

已知图中所示的三根弹簧的劲度系数分别为K₁，K₂，K₃，振体的质量为m，则此系统沿铅垂方向振动的固有频率为（）。

A.

B.

C.

D.