下列对空气的描述不正确的是　(  )

阅读下列内容，从每小题所给的A、B、C、D四个选项中选出一个最佳答案。

    Attention！Sunshine Language Learning Centre will set a course and it will teach Pure（纯正的） British English. Maybe you've known some British expressions are quite different from American ones。British people use “autumn” for “fall”, “film” for “movie”. “holiday” for “vocation”, “garden” for “yard”. etc

    There are more typical（典型的）expressions that you may not know. Here are Mr. Bean's examples.

    Are you interested in it? Do you want to learn? You can learn British English well if you put much effort into it. We have some native British English teachers with much experience to help you.

    The course will be open in the coming summer holiday. The price of the course is not very high: ￥500 for one person; ￥900 for two（10% off）; ￥1,200 for three (20% off); for four or more(30% off).

    For further details, call 400-810-2345 or search http://www.BEcourse.com. Come and join us!

作文
        人生从来没有真正的绝境，无论遭受多少艰辛，无论经历多少苦难，只要一个人的心中怀着自信，那么总有一天能走出困境，让生命重新开花结果。
        请以“带着自信前行”为题，写一篇记叙文。
       要求：①选材真实，情感真挚。
       ②不少于600字。
        ③文中不要出现真实的校名、班级名、人名。

竹子是“有节、中空、四季常绿”的植物．同学们对竹子中的气体成分展开了探究，测定其成分．

（1）收集竹子中的气体．

小华提出：将一节竹子浸没在水中，在竹子上钻孔，用排水法收集气体．

小刚提出：可用注射器从竹子中抽取气体．

大家认为两人的想法都可行，于是分为A、B两组，在相同的条件下，A组采用小华的取气方法，B组采用小刚的取气方法，分别完成下面的实验．

（2）检验气体中是否含有二氧化碳气体．