用定量研究的方法得出了空气是由氮气和氧气组成的科学家是（　　）

短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1）. 每处错误及其修改均仅限一词；

2）. 只允许修改10处，多者（从第11处起）不计分。

    As we know, when senior students finish their school, most of their reference books are thrown away, which are still in good condition. How a great waste it is!

    I suggest that students must recycle all these books. On the one hand, recycling them can save a lot of natural resource, which are used to make textbooks. On the other hand, the notes in the books are helpful to whoever need them.

    In fact, recycling textbooks has been increasing popular in such countries like America and Australia. We should learn from them, but make every effort to build energy-saving society. In my opinion, it is of much benefit from our present and our future.

决定青春的最重要的因素是（   ）

某粒子的结构示意图为，下列说法中不正确的是(    )