下面短文中有10处语言错误。请在有错误的地方增加、删除或修改某个单词。
增加：在缺词处加上一个漏字符号(∧)，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，并在该词下面写上修改后的词。
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11处起) 不计分。
Dear Mr Black,
I'm very thank to you for inviting me to stay with you in the come summer vacation. I have been dreamed of seeing you again so that I can get more help from you in my English learning. And I'm afraid I cannot go to your place in this summer. I've promised my grandmother, she lives in the country, to spend this summer with her. She misses me too much that I find difficult to refuse her request.
I'm busy with preparing for my examinations at present. I planned to visit you in winter if it's convenient to you.
Best wishes.
Yours truly,
Li Ying