两个连续奇数的平方差能被8整除吗？请说明你的理由．_爱下问搜题

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问题解答题

两个连续奇数的平方差能被8整除吗？请说明你的理由．

答案

两个连续奇数的平方差能被8整除．

理由：设这两个连续奇数分别为：（2n+1）与（2n-1），

∵（2n+1）²-（2n-1）²=（2n+1+2n-1）（2n+1-2n+1）=4n×2=8n．

∴两个连续奇数的平方差能被8整除．

完形填空

阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑
Half a year before graduation from college, my son began to seek a job.  the financial crisis, fewer companies would like to    new staff. My son targeted a company that was  to employ only one person   there were more than 20 people filing their resumes.
After the interview, there would only be 3 who could enter the final round, which would later   one person to be employed. Everything seemed to go quite    and my son passed the first round and entered the final round in a week.
On the day of the final interview, my son and other two    arrived at the interview place on time,   the test. The interview was unbelievably . The interviewer only said to them, “All of you are very super. Please go home and wait for our   . We will tell you the    in 3 days. Good luck to all of you！” On the morning of the third day, my son received a text from the company shortly after breakfast that he was not employed. We all felt very   .
In nightfall that day, my son suddenly told me    on phone, “Dad, I have been employed!” Greatly surprised, I could not wait to ask him, “ What’s the whole   ?” My son told me that he received another text saying that he was employed. Actually the first text sent to my son was also    of the test in the interview. Three men received the same text this morning and only my son ’s    was “ Thank you” while the others said “Goodbye”.
Only then did I know that my son ’s hope    in that way. That is, when you feel disappointed, do not    to say “Thank you ” to the one who disappoints you. Saying “Thank you” shows respect for others’ work and shows your grand   . Therefore, while under the same condition, you will get the upper hand in terms of    compared with others!

D．Contrary to

A．watching over

B．waiting for

C．thinking about

D．looking into

A．information

D．disappointed

D．personality

B．opportunities

单项选择题

混合物在CMEX系列X射线机中显示的颜色为（）

A.红色

B.橙色

C.绿色

D.蓝色