题干

下列反应过程中的能量变化与如图相符的是(   )

A:金属钠和水反应

B:生石灰变成熟石灰的反应

C:Al和Fe2O3的铝热反应

D:CaCO3受热分解

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答案(点此获取答案解析)

D

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    Gadgets that make study fun

    Now in a world piled high with smart phones, tablets and e-readers, technology has entered the classroom in ways unimaginable. Taking classes can be fun too. All you have to do is swipe your fingers on your phone screen and download some apps, which can make your study more fun and efficient. Balancing study and play in a college setting has never been easy-and with the following few apps, it'll be tough to tell the two apart.

    Evernote

    Use: note-taking

    Can be used on: Phone/iPad/iPod touch, Android, BlackBerry, Palm OS and     Windows, Phone 7

    Price: free

    It's hard to imagine that with all the magical gadgets, the eager, studious types would still take out a notepad, a pencil, and a highlighter—and take notes in class. While it's not an actual planner or a calendar App, if you take notes to stay organized, then Evernote is for you.The main thing about Evernote is that all of your notes are automatically sent into the cloud---and then you can access them from any web-connected computer via the Evernote app or a web browser. Evernote also supports audio and photo notes-rather handy if you want to record your lecture or take photos of any projected notes. But, of course, ask for permission first.

    Wikipanion

    Use: research database

    Can be used on: iPhone/iPad/iPod touch

    Price :free ( Wikipanion Plus for $4.99,or 31.87 yuan )

    Now, you don't necessarily have to go to a library or anywhere with computer services to do research work for your paper anymore. You can get access to the research databases just on your smart phone or tablet. Wikipanion gives you a simplified version of Wikipedia without leaving out any of the site's extra features. The normal links that you'd see to each section of an article are no longer on the main screen. Instead, there's small icon located at the bottom of the App, which can be used to access all the sections of an article. You can also open the links in Safari(苹果浏览器). According to the developers' site, loading Wikipedia pages with Wikipanion is a lot faster than accessing the Wikipedia site from the iPhone's browsers. To be honest, we agree.

    Conquering Bilingual News Listening in 7 Days

    Use: English learning application

    Can be used on: iPhone/iPad/iPod touch

    Price: For a limited time you can get the App for only $0.99—half price.

    Still learning English with a workbook? If so, you are behind the times. Get 21st Century Newspaper's new iPhone App, “Conquering Bilingual News Listening in 7 Days”. When you download the App on your iPhone, you can listen to the hottest bilingual news selected from the newspaper's official website (w. w. w. i2lst. cn) and read by native speakers. User can enjoy the audio bilingual news with synchronized subtitles and fantastic pictures while immersed in an authentic language environment. With a simple tap, the sentence you choose will be repeated. “Conquering Bilingual News Listening in 7 Days” has ranked No 1 on the Chinese education App list.