题目内容
【B18】
查看答案
搜索结果不匹配？点我反馈
更多问题
根据下图，回答下面问题
注：图中曲线从上到下依次是“农村”、“全国”、“城市”的居民消费价格指数。
2008年3月份全国居民消费价格指数(CPI)同比约上涨()
TV Goes Digital
Coming soon to your TV: views of the hottest live basketball plays from any seat in the stadium. What a better look at that three-point shot？ Call for a replay from behind the basket. Or better yet, follow the "view" of the ball as it goes through the net.
While watching, you might use a built-in speakerphone to talk with a fan in the stands. Or send the score via email to your father in Japan. Sounds impossible？ It won't be when the computerized television industries combine to create digital TV machines that receive, send, store, and manipulate TV programs the way computers now manipulate other data;
Industry and government representatives recently reached an agreement on how this technology will take place. New digital TVs that allow current TVs to receive digital signals may hit stores by next spring.
To understand how the digital revolution will change the way you watch TV it helps to know how TVs work now. Today, TV networks such as CBS and Fox broadcast; TV shows as analogue electrical signals; These signals travel via the airwaves, satellites; or cable as a continuous stream of electromagnetic energy (like light and radio waves). But this system leaves a lot of room for error. The main problem is that interference can change the voltage of the signal as it travels. This may result in a distorted or miscolored picture. If we send out the signal in a form. that is nearly free from interference-binary(两位数的)code, pictures and colors are not distorted.
you'll need to buy a new TV to receive these signals. And the new sets may cost 1,000 US dollars more than today's TVs. But they'll come with other benefits that may make the price worthwhile. For one thing, the screens will be wider, like movie screens. In addition, the color will be richer. And you'll also get digital CD-quality sound.
Besides these benefits, digital TVs can offer you a much wider choice of programs. Digital data can expand TV choices because computers can compress digital signals. Broadcasters will be able to send six times as much information on the same "channel".
All the following qualities are mentioned in the passage EXCEPT ______.
右边的第4个图形应该是哪个选项()。
挡土墙高h=5m，墙背竖直，填土表面水平，填土为砂土，其重度了γ＝18kN/m3，内摩擦角Φ=30°，如下图所示。
墙底处(Z=h=5m)的压力强度与 ______值接近。
微信支付 
支付宝支付