题干

某热电厂使用的燃料是含硫较多的煤,附近的居民们经常闻到空气有异味。他们怀疑该厂排放出的SO2超标了,于是请兴趣小组的同学帮助测定空气中SO2的含量。

【设计实验】兴趣小组的同学设计以下步骤来测定空气中SO2的含量。

①用2L的空可乐瓶采集工厂附近的空气样品。

②向取回的装有空气样品的可乐瓶中少量、多次加入NaOH溶液,每次加入NaOH溶液后都盖紧瓶塞并充分振荡,直至可乐瓶中SO2被完全反应。

③加入一定量氧化剂H2O2,使其中Na2SO3完全转化为Na2SO4。并向可乐瓶中加入过量的BaCl2溶液。

④经过过滤、洗涤、烘干,称量固体质量。

⑤根据固体质量计算出SO2的质量,并计算出空气中SO2的含量。

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    We've all experienced peer pressure (同伴压力). It happens to everybody. However, people have different reactions. Confident people refuse to do things they don't want to do, but shy and anxious people often give in. It may be because they want to be liked. It may be because they worry that their friends will make fun of them, or perhaps they're just curious about trying something new. ____

    It's hard being the only one who says no and the question is: how do you do it? ____ If you think that missing maths, or smoking, or going somewhere you know your parents wouldn't like is a bad idea then the answer is simple: don't do it. It's your decision, nobody else's. You don't need to be aggressive. You don't need to shout and scream, but you must be confident and you must be firm. You need to say, “No thanks. I don't want to do that.”

    Being on your own against everybody else is very hard, so it can really help to have at least one other peer, or friend, who will say no too. ____ You want friends who will support you when you're in trouble. You don't want people who will always agree with the majority. Remember, the most popular people aren't always the most trustworthy.

____ — You can learn a lot from people your own age. They can teach you great football skills or the best way to do your maths homework. They can recommend music and advise you on fashion. And don't forget you can tell them things too, and that always feels great. So, find friends who have similar interests. And remember, friendship isn't about feeling depressed and guilty. ____

A. Choose your friends carefully.

B. Firstly, you must decide what you believe in.

C. It's about sharing experiences and having fun.

D. Of course, peer pressure isn't completely bad.

E. It may be because they were all born to be stubborn.

F. Depression and guilt will surely give you peer pressure.

G. Whatever the reason, some people end up doing things they really don't want to.