龈上边缘适用于（）。 A.金瓷冠的唇侧 B.老年患者牙龈退缩明显 C.牙冠短小 D.

A total of 4.6 million digital televisions have been sold, and the sales of HDTV sets have quadrupled since last year. Consumers have bought HDTVs to play their DVDs and to have clearer pictures and wide screens. Only a small percentage of the people who have purchased HDTVs, however, have actually hooked their TVs up to receive high-definition television digital signals. Perhaps television viewers are having trouble keeping up with the changes in technology. Even the manufacturers of HDTVs, like Mitsubishi, Thomson Multimedia, Sony, and Samsung seem to have a tough time learning how to make their sets work with the various digital TV formats because little standardization has been required or implemented in the industry.

Some of the HDTVs weigh over 200 lbs., and a variety of retailers offer a delivery service to the buyer’s home to help install the heavy sets. This is known as a white-glove service and usually comes with an extra fee. After HDTV purchasers get their sets home and hook them up, they will still need to work to get the digital signals to their systems. Most of the industry’s cable providers do not yet offer high~definition programing, and only about 15% of commercial television stations have switched over to even the lowest improved digital pictures. Worse yet, viewers may need to install antenna before they can even get the digital signals to their new HDTV sets. Another frustration for home-theater seekers is that the current HDTV sets allow owners only to watch high-definition programs, not to record them.

According to the first sentence, the sales of HDTV sets since last year, by the time when this article was written, had reached ().

A. 4.6 million

B. 9.2 million

C. 18.4 million

D. I do not know how many

场景（七）

某建筑公司中标了一个房建工程，该工程地上三层，地下一层，现浇混凝土框架结构，自拌C30混凝土，内隔墙采用加气混凝土砌块，双坡屋面，防水材料为3厚SBS防水卷材，外墙为玻璃幕墙。生产技术科编制了安全专项施工方案和环境保护方案。一层混凝土浇捣时，项目部针对现场自拌混凝土容易出现强度等级不够的质量通病，制定了有效的防治措施。一层楼板混凝土浇筑完毕后，质检人员发现木工班组不按规定拆模。

根据场景（七），作答下列题目：

该单位工程的临时供电工程专用的电源中性点直接接地的220/380V三相四线制低压电力系统，必须符合（）的规定。

A．采用二级配电系统

B．采用三级配电系统

C．采用一级漏电保护系统

D．采用二级漏电保护系统

E．采用TN-S接零保护系统

强夯法亦称为（）。

A．强力夯实法

B．动力排水法

C．动力固结法

D．夯实填充法

侵犯皮肤表面的接触性急性化脓性感染是

A．痈
B．疖
C．蜂窝织炎
D．丹毒
E．脓疱疮

春温热郁胆腑，选方为（）。