简述GSM网络中直放站(中继器)的功能及其工作原理。
答：直放站的基本功能就是一个射频信号功率增强器。直放站在下行链路中，由施主天线现有的覆盖区域中拾取信号，通过带通滤波器对带通外的信号进行极好的隔离，将滤波的信号经功放放大后再次发射到待覆盖区域。在上行链接路径中，覆盖区域内的移动台手机的信号以同样的工作方式由上行放大链路处理后发射到相应基站，从而达到基地站与手机的信号传递。
暂无解析
她有能力做这项工作。(ability)
If you do not find the required information using the tips from the previous section, then you need to consult an online service to find the piece of information you were looking for. Three different types of services have been established over the years: crawlers, directories and meta search engines. The first crawler was created back in 1993. It was called the World Wide Worm. It crawled from one site to the next and indexed all pages by saving the content of the web pages into a huge database. Crawlers or spiders visit a web page, read it, and then follow links to other pages within the site and even follow links to other sites. Web crawlers return to each site on a regular basis, such as every month or two, to look for changes. Everything a crawler finds goes into a database, which people are able to query. The advantage of the web crawlers is that they have an extensive database with almost the complete Internet indexed in it. The disadvantage is that you get thousands of web pages as a response for almost any request. Web directories work a little differently. First of all they contain a structured tree of information. All information entered into this tree is either entered by the webmaster who wants to announce his new web page or by the directory maintainer who looks at the web pages submitted. The directories where webmasters can submit both the URL (Uniform Resource Locator) and the description normally contain more misleading information. Getting into most web directories is a combination of luck and quality. Although anyone is able to submit a web page, there is no guarantee that a certain page will be included. Some directories charge for submission, which is basically a rip-off. Some crawlers maintain an associated directory. If your site is in the directory, the ranking of your web site normally will be higher, as it is already pre-classified. Many directories work with crawlers together, in order to deliver results, when nothing can be found in the directory. Meta search engines do not have a database with URLs and descriptions. Instead they have a database of search engines. If you enter your keywords into a meta search engine it will send out requests to all the directories and crawlers it has stored in its database. The meta search engines with a more sophisticated application in the background are able to detect double URLs which come back from the various search engines and present only a single URL to the customer.
34. Crawler is a kind of__________.
A. worm B. search engine C. service D. directory
35. The disadvantage of Crawler is that it__________.
A. provides a complete database
B. takes too much time to find the needed information
C. provides too much useless information
D. gives response to every quest
36. Who can input information to the web directories?
A. Only webmasters.
B. Both directory maintainers and webmasters.
C. Any one who wants to announce a web page.
D. Any one who has found a new web page.
简述我国教育目的的基本特征。
翻译：in vain
翻译：algorithm
简述银行参与的支付过程的两个层次。
简述学校管理过程中执行的作用。
试述电子商务网站的设计要求。
定量分析。
名词解释：保护性管辖权