下列函数f（x）中，满足“对任意x₁、x₂∈（0，+∞），当x₁＜x₂时，都有f（x₁）＞f（x₂）的是（　　）

我国先后在南极地区建立了长城站、中山站和昆仑站三个极地科学考察站，建站时间一般选在2月份，其原因是此时（    ）

请结合此实验完成下列问题：

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 all know, we can meet with various challenges in our life. Faced with challenges, how should we do?

    Last month, our class climbed Mount Tai, that is more than 1,500 meters above sea level. Lacking exercise, I thought that this activity was great challenge for me. I felt very exhausted halfway that I wanted to give up. See this, my classmates and even some strangers encourage me. By the end, I managed to reach on the top of the mountain.

    Therefore, don't give up in face of challenges. If you are determined enough, it's certainly that you can overcome it.