设已知某公司2001年至2009年的产品销售额资料如表1所示。表1请根据上述资料对该公司的产品销售趋势进行分析，从下列各题的备选答案中选出正确答案。
设直线趋势方程的一般形式为
，其中
表示销售额Yt的趋势值，t代表时间序号（令2005年t=0），则a与b的含义是（）。
A.a代表趋势线的斜率，b代表趋势线的Y截距
B.a代表趋势线的Y截距，b代表趋势线的斜率
C.a代表趋势线的斜率，b代表趋势线的t截距
D.a代表趋势线的t截距，b代表趋势线的斜率
参考答案：B
| 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. |
On the whole, this passage is positioned to dwell on______.
A．the overall picture of the HDTV sector
B．how the giant TV makers should offer better products
C．a lament over consumers’ inability to use a high-end TV set
D．a criticism of the.TV makers for doing nothing about a big problem