邮资票品的发行包含有（）的职能。 A.国家货币发行 B.国家行政管理 C.邮政行政管

Go _____ the park and _____ right.  [ ]

A. to; to                      

B. on; turn             

C. down; turn                   

D. to; turn

决定平抛物体在空中运动时间的因素是[ ]

A．初速度

B．抛出时物体的高度

C．抛出时物体的高度和初速度

D．以上说法都不正确

必要条件假言命题只有在哪种情况下才是假的（）？

A、前件真后件假

B、前后件都真

C、前件假，后件真

D、前后件都假

Until the late 1940s, when television began finding its way into American homes, companies relied mainly on print and radio to promote their products and services. The advent of television (1) a revolution in product and service. Between 1949 and 1951, advertising on television grew 960 percent. Today the Internet is once again (2) promotion. By going online, companies can communicate instantly and directly with prospective customers. (3) on the World Wide Web includes advertising, sponsorships, and sales promotions (4) sweepstakes, contests, coupons, and rebates. In 1996 World Wide Web advertising revenues (5) $ 300 million.

Effective online marketers don’t (6) transfer hard-copy ads to cyberspace. (7) sites blend promotional and non-promotional information indirectly delivering the advertising messages. To (8) visits to their sites and to create and (9) customer loyalty, companies change information frequently and provide many opportunities for (10) .

A prototype for excellent (11) promotion is the Ragu Web site. Here visitors can find thirty-six pasta recipes, take Italian lessons, and view an Italian film festival, (12) they will find no traditional ads. (13) subtle is the mix of product and promotion that visitors hardly know an advertising message has been (14) . Sega of America, maker of computer games and hardware, uses its Web site for a (15) of different promotions, such as (16) new game characters to the public and supplying Web surfers the opportunity to (17) games. Sega’s home page averages 250,000 visits a day. To heighten interest in the site, Sega bought an advertising banner on Netscape (18) increasing site visits by 15 percent. Online (19) in Quaker Oats’ Gatorade promotion received a free T-shirt in exchange for answering a few questions. Quaker Oats reports that the online promotion created product (20) and helped the company know its customers better.

13（）

A.Since

B.However

C.Such

D.So

目前我们调测时钟采用的频率计主要是什么材料构成？（）

A、原子

B、铷

C、铯

D、电子