人口增长过快产生的问题是（　　）

某校八年级学生小利，多次受到三个不法分子的勒索。第一次，他们要她交50元“保护费”，声称不给便要打她，不准她上学，她只好把存起来的零用钱给了他们。三天后，他们又要她交出100元，声称不给便要划破她的脸，她只好偷偷地向别人借钱，凑足钱款给他们。但过了不到一星期，这些人又来胁迫，要她交出500元。一个初中生哪来这么多钱？他们便把她劫持到一个旅馆，企图侮辱她。幸亏被旅馆保安人员发现，才把她救了出来。
阅读上述材料，结合所学知识，回答下列问题：

假定英语课上老师要求同桌之间交换修改作文,请你修改同桌写的以下作文,文中共有10处语言错误,每句中最多有两处,错误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(∧),并在此符号下面写出该加的词。 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).每处错误及其修改均仅限一词;

2).只允许修改10处,多者(从第11处起)不计分。

Boys and girls,

    May I have your attention, please?

    There will a lecture in our library, at 4:00 on Wednesday afternoon. We are very honour to have invited Professor Tang Wenfang, who has been studied cultural differences in Tsinghua University for many years, in talk about the differences between American and Chinese cultures, that may be quite an interested topic. After a lecture, you are welcome to share your experience in China with everyone else present. Since you have stayed in China for half a year, because you have anything that what puzzles you, it would be great to talk with Mr.Tang. He will be glad to communicate with you. Please be present on time.

    That's all. Thank you.

在电场中的某点放一个检验电荷，其电量为q，受到的电场力为F，则该点的电场强度为$E=\frac{F}{q}$，下列说法正确的是（   ）