题目内容
根据乔姆斯基20世纪50年代建立的形式语言的理论体系，语言的文法被分为四种类型，即：O型(上下文有关文法)、1型(上下文相关文法)、2型(上下文无关文法)和3型(正规文法)。其中2型文法与(66)等价，所以有足够的能力描述多数现今程序设计的语言的句法结构。一个非确定的有限自动机必存在一个与之等价(67)。从文法描述语言的能力来说，(68)最强，(69)最弱，由四类文法的定义可知：(70)必是2型文法。
(40)
查看答案
搜索结果不匹配？点我反馈
更多问题
假如程序员可用的存储空间为4M字节，则程序员所用的地址为(16)，而真正访问内存的地址称为(17)。
(45)
are individuals and organizations that are actively involved in the project，or whose
某项目中有两个活动单元：活动一和活动二，其中活动一结束后活动二才能结束。能正确表示这两个活动之间依赖关系的前导图是(38)。
Credibility about messages is high, because they are reported in independent media. A newspaper review of a movie has more believability than an ad in the same paper, because the reader associates independence with objectivity. Similarly, people are more likely to pay attention to news reports than ads. Readers spend time reading the stories, but they flip through the ads. Furthermore, there may be 10 commercials during a half-hour television program or hundreds of ads in a magazine. Feature stories arc much fewer in number and stand out clearly.
Publicity also has some significant limitations. A firm has little control over messages, their timing, their placement, or their coverage by a given medium. It may issue detailed news releases and find only portions cited by the media; and media have the ability to be much more critical than a company would like. For example, in 1982, Procter & Gamble faced a substantial publicity problem over the meaning of its 123-year-old company logo. A few ministers and other private citizens believed that the symbol was sacrilegious. These beliefs were covered extensively by the media and resulted in the firm receiving 15,000 phone calls about the rumor in June alone. To combat this negative publicity, the firm issued news releases featuring prominent clergy that refuted the rumors, threatened to sue those people spreading the stories, and had a spokesperson appear on Good Morning America. The media cooperated with the company and the false rumor was temporarily put to rest. However, in 1985, negative publicity became so disruptive that Procter & Gamble decided to remove the logo from its products.
A firm may want publicity during certain periods, such as when a new product is introduced or new store opened, but the media may not cover the introduction or opening until after the time it would aid the firm. Similarly, media determine the placement of a story; it may follow a report on crime or sports. Finally, the media ascertain whether to cover a story at all and the amount of coverage to be devoted to it. A company- sponsored jobs program might go unreported or receive three-sentence coverage in a local newspaper.
The author mentions all of the following advantages of publicity EXCEPT ______.
微信支付 
支付宝支付