人发制滤布

化学肥料可以促进农作物生长。现有一种常见的化学肥料，由A、B、C、D四种元素组成。其中A元素为地壳中含量最高的元素；B元素是氮；C元素形成的单质是所有物质中相对分子质量最小的；D元素与氧元素可形成一种组成为DO₂的化合物，它在绿色植物的光合作用中扮演重要角色。

(1)写出三种元素的元素符号：A_______，C_________，D_________。

(2)试写出该肥料的化学式________（写一种即可）。

读“北京和新加坡气候图”，回答下列问题。

（1）两个城市中气温年较差较大的是                   ，年平均气温较高的城市是                   。

（2）两个城市中年降水量较多的是                   ；北京         月的降水量最多。

（3）你如何描述北京的气候特征？                                                                                                  

通过权威人物的正面训导以激起或强化人们的危机意识称为（）

A.间歇强化

B.曲线强化

C.正面强化

D.负面强化

肝包虫病最常见的治疗方法是

A．包囊及部分肝切除术

B．内引流术

C．包虫囊肿内囊摘除术

D．药物治疗

E．包囊完整切除术

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.

11（）

A.internet

B.online

C.current

D.predominant