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。

Dear Ms Smith,

    I am secretary of the City Student Union (CSU).We were organizing an art exhibition for high school students in city.This will be held on the 9^th of July in the Exhibition Hall of Beihai.More than 1000 painting will be on show, but high school students and teachers from all the eight districts will come to the event.As you are very popularly with us Chinese high school students,we'd like to invite for you to the exhibition.We would be grateful when you could join them that day.Looking forward to hear from you soon.

Yours,

Li Ming

人口迁移率指人口迁移数占总人口数的比例，正值为迁入。图中甲、乙、丙、丁各代表一个国家，依次是(   )

满足线性约束条件$\left\{\begin{array}{c}\begin{array}{c}2x+y\le 3\\ x+2y\le 3\\ x\ge 0\end{array}\\ y\ge 0\end{array}\right.$的目标函数z=x+y的最大值是（   ）