已知向量，且，若变量x,y满足约束条件
则z的最大值为

关于图中“坐地日行八万里”解释错误的是（  ）

This is __________ teacher.

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语法错误，每句中最多有两处错误。每处错误仅设计一个单词的增加，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。
Dear Lucy,
    I am very excited to learn that you're coming to Xi'an for travel. Both my parent miss you a lot. So is our friend, Ruby. April is best time of the year to visit Xi'an. There is only a few rain and the weather is neither too hot or too cold. There are so many places I wanted to take you to after I finish my work like a volunteer in the local charity. When you come, you can stay with ourselves. My house is about three kilometers far away from Xi'an Moslem Street where is full of local foods.
Best regards,
                                                                                                                                                Janet

读图，判断（1）～（5）题．