题干

用NA表示阿伏伽德罗常数的值。下列叙述正确的是(      )

A:25℃时,pH=13的Ba(OH)2溶液中含有的OH数目为0.2NA

B:标准状况下,2.24LCl2与过量的稀NaOH 溶液反应,转移电子总数为0.2NA

C:室温下,46.0gN2O4和NO2的混合气体中含有的原子数目为3NA

D:78gNa2O2固体中含有的阴离子数为2NA

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C

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    In this day and age taking a photograph is easier than ever. There are cameras built into our phones, computers, iPods…The way we share photos has also changed. There was a time when you'd print your photos and put them into photo albums, but because of the advance in technology, all in technology, all this has changed.

    Not only do we have what seems like an endless amount of space to store photos on our devices, but we also have the Internet, especially social media. Social networks such as Facebook allow us to post our pictures and albums to share friends and family.

    While you could argue this easy ability to store, share and enjoy photos is fantastic, it could also be said that photographs have lost some of their meaning. I have over 1000 pictures on my smart phone and several thousand stored on my computer. I love posting my pictures on Facebook. Sometimes, however, I try to ask myself, will I really want to look back at this picture of a coffee or a selfie taken in a bathroom by myself? Probably not.

    Even though I'm guilty about sometimes taking meaningless and boring pictures like this, a couple of years ago, I decided to find a way to make my photographs more meaningful. How did I do this? Disposable (一次性)cameras! When I go on a trip, I always try to take a disposable camera. With only 27 pictures you can take, you really think about the photograph straight away. And finally, it's so much fun to get the pictures developed and look through them again.

    I admit that I couldn't live without social media or taking photographs with my smart phone, but I do think taking photographs has become less meaningful. That's why I'll continue using disposable cameras. It's a great way to make your photographs more meaningful.