自由运动的滚摆,每次上升的高度逐渐减小,下列说法正确的是:[ ] A.机械能守恒

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问题:

自由运动的滚摆,每次上升的高度逐渐减小,下列说法正确的是:[ ]

A.机械能守恒

B.能量正在消失

C.只存在动能和重力势能相互转化

D.减少的那部分机械能转化为内能,但总的能量守恒

考点:能量守恒定律
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小郭和小万在讨论这次学校“艺翔助学金”发放的一些情况。
小郭:这次没有女生获得“艺翔助学金”的资助。
小万:那就是说这次全校的“艺翔助学金”的名额都空缺了。
小郭:不,事实上这次咱们学校有几位男生获得了“艺翔助学金”。
以下各项断定如果为真,都能使小万的推断成立,除了________

A.“艺翔助学金”的申请者中,大部分的女生比大部分的男生更够条件。
B.只有女生才有资格申请“艺翔助学金”。
C.“艺翔助学金”的申请者中,所有的女生都比男生更够条件。
D.按规定,男生和女生必须获得相等数量的“艺翔助学金”名额。
E.“艺翔助学金”只发给女生。

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二氧化钛

A.成型材料
B.增塑剂
C.遮光剂
D.防腐剂
E.增稠剂

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Maybe you’re really busy. Maybe you don’t have much to say. Or maybe you’re just lazy. Not a problem. This free service works by letting you broadcast a group text message to your {fiends’ mobile phones from either your own phone, an instant message or an online form at twitter, com. All your notes are then stored and displayed on your personal profile page on the site, which includes links to your friends’ Twitter pages, a thumbnail picture of your choice, and a short bio. All this is what the new service Twitter can bring you. Just remember to keep it short: posts are limited to !40 characters, and the topic is, invariably, “What are you doing?”

More often than not, it turns out, Twitter’s 100,00 members--twice as many as it had just a month ago, according to Twitter business development director Biz Stone--are simply killing time. Even Presidential hopeful John Edwards is on it, although he seems to be the only one thinking about more than lunch. As I type this, Caroline is mulling over some Girl Scout cookies, Ian Hocking is “waiting for Jessica to arrive so we can eat!” and Hlantz is “having a nice cup of Soft Starmint tea.”

The chatter (闲话) about Twitter turned into a virtual roar two weeks ago during the South by Southwest Multimedia Festival in Austin, Texas, when the barebones service owned by Blogger founder Evan Williams, 34, was named the best blogging tool and attendees used it to meet up at parties. Nevertheless, Twitter has been the top term on blog search engine Technorati for the past two weeks.

Plenty of people would happily have Twitter silenced, rather than tolerate the beeping alert for yet another new text message. But I’m betting that Twitter will get a lot noisier before netizens move on to the next new thing. We cyberjunkies need a new thrill, and what is better than a service like Twitter that combines social networking, blogging and texting? And if you don’t like it, well, in the words of one Twit from San Francisco, “I’m so sick to death of Twitter-haters. If you don’t like it, why waste your time writing, reading, or talking about it?”

1. This text is intended to __________.

A. point out the virtues and faults of Twitter    B. tell people how to use Twitter to communicate

C. give a general outline of Twitter. Com       D. introduce a new and easy way of instant communication

2. According to the text, Twitter is designed mainly for the purpose of ___________.

A. promoting products and services             B. talking about small daily things

C. discussing serious social matters              D. attracting voters for presidential election

3. We know from the text that Twitter may be superior to Blogger in that ________.

A. it limits each user’s texting under 140 words                  B. it saves users’ time and thinking

C. it can be easily operated through users’ mobile phones

D. it is newly invented by Blogger owner Evan Williams

4. By quoting one Twit from San Francisco, the author implies that ___________.

A. like it or not, Twitter will be accepted by more and more people

B. if one doesn’t like Twitter, he/she can choose not to mention it

C. writing, reading and talking about Twitter is a waste of time

D. twitter users naturally have a strong dislike for non-Twitter users

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调节保证计算

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年金

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