问题 填空题

(15分)下列物质①铁 ②干冰 ③金刚石 ④铜 ⑤水晶 ⑥氯化钠 ⑦单质碘⑧氢氧化钠【请用编号回答(1)和(2)小题】

(1)属于离子晶体的是   ,属于分子晶体的是   ,属于原子晶体的是   ,属于金属晶体的是   

(2)只含共价键(不含分子间作用力)的化合物是   ,只含离子键的是   ,既含共价键又含离子键的是   

(3)写出电子式:干冰       ,氢氧化钠       

(4)写出结构式:干冰       ,单质碘       

答案

(共15分)

(1) ⑥⑧②⑦③⑤①④(每空2分,对一个得1分,错一个扣1分,扣完2分为止。)

(2) (每空1分)

(3) (每空1分)

(4) O="C=O" 、 I—I(每空1分)

铁、铜为含有金属键的金属晶体;而干冰、碘为含有共价键、分子间力的分子晶体;金刚石、水晶为含有共价键的原子晶体;氯化钠、氢氧化钠为离子晶体,前者只含有离子键,后者还含有共价键。

单项选择题
阅读理解

On March 28th, the New York Times will begin charging all but the most infrequent users to read articles online.

In a letter to readers, Arthur Sulzberger, Jr., the publisher of the paper, laid out the details of the paywall, which he said will go into effect immediately in Canada and on March 28th for the rest of the world. He called the move “an important step that we hope you will see as an investment in the Times, one that will strengthen our ability to provide high-quality journalism to readers around the world and on any platform.”

Sulzberger said that readers will be able to read 20 articles per month at no charge. Once they click on the 21st piece, however, they’ll be presented with three payment options: $ 15 for four weeks of online and mobile application access, $ 20 for access to the site and the iPad application, or $ 35 for access to everything. People who already receive the printed paper through home delivery will enjoy free and unlimited access to the Times on all platforms.

These details largely agree with earlier reports on how the paywall would work. The Times had made it clear that it did not want to imitate the total paywalls put into effect by papers such as The Times of London and Newsday, which block access to all contents unless the reader pays.

The paper also signaled that it wants to stay relevant in the social media world. According to Sulzberger's announcement, people who come to the Times site from Facebook, Twitter or from blogs will be able to read those articles even if they have gone over their monthly limit.

However, Sulzberger said that a limit will be placed on “some search engines”, meaning that after readers have accessed a certain number of articles from search engines, any further articles they access from there will be added to their monthly count. It was reported that the only search engine that will be affected this way is Google, where there will be a five-article limit. This marks a clear attempt by the Times to close what could be a giant loophole (漏洞), since so much online traffic is directed through Google. But it also presents a risk for the Times for the same reason.

Sulzberger seems well aware of the risk. “The challenge now is to put a price on our work without walling ourselves off from the global network,” he said, adding that the Times must “continue to engage with the widest possible audience.”

小题1:The author’s main purpose in the text is to _______.

A.describe research findings

B.report a piece of news

C.make advertisements

D.suggest a solution小题2:Why will the Times charge their online readers?

A.It wants to stay relevant in the social media world.

B.It has too many readers coming from the other sites.

C.It is seeking new financial sources for its development.

D.It is trying a way to offer better service to its readers.小题3:Who will be limited to the New York Times articles?

A.Those subscribing to the printed newspapers

B.Readers clicking through from Facebook.

C.Those using Google research engine

D.Readers paying $ 35 a month.小题4:What challenge may the paywall bring to the New York Times?

A.It may bring the Times more competition with the other media

B.It may stop the Times connecting to the global network

C.It may block the readers from the other websites

D.It may result in huge drops in papers' online readership