某同学用打点计时器测量做匀加速直线运动的物体的加速度，电源频率f=50Hz．在纸带上打出的点中，选出零点，每隔4个点取1个计数点．因保存不当，纸带被污染．如图所示，A、B、C、D是依次排列的4个计数点，仅能读出其中3个计数点到零点的距离：x_A=16.6mm、x_B=126.5mm、x_D=624.5mm，若无法再做实验，可由以上信息推知：

（Ⅰ）求证：数列{a_n}为等差数列；

（Ⅱ）试求所有的正整数m，使得 $\frac{{\text{a}}_{\text{m}}{}^{\text{2}}{\text{+a}}_{\text{m+1}}{}^{\text{2}}-{\text{a}}_{\text{m+2}}{}^{\text{2}}}{{\text{a}}_{\text{m}}{\text{a}}_{\text{m+1}}}$ 为整数；

（Ⅲ）若对任意的n∈N^*，不等式 $\lambda {\text{T}}_{\text{n}}\text{<n+}\frac{\text{2}}{\text{3}}•{\left(-\text{1}\right)}^{\text{n+1}}$ 恒成立，求实数λ的取值范围．

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：在错的词下画一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改仅限一词；

2）只允许修改10处，多者（从第11处起）不计分。

    I am good at English and always get high marks in English test. Last month, an English speech contest held in our school. I take part on behalf of our class. Proud of my excellently English, I ignored my teacher's advice but didn't prepare for the contest at all. The important day came in. When it was my turn, I walked onto a stage confidently. However, the moment I saw the speech topic, my mind went complete blank. I was at a loss for words because I knew something about the topic. Filled with regret and shame, I learned a good lesson: pride comes after a fall.

读一读，写一写。