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（＼）划掉。

修改：在错的词下画横线, 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。

    Thank you for your invitation to dinner at your home tomorrow evening. Unfortunately, it is much to my regret which I cannot join in you and your family. I will be full occupied with an important exam come the day after tomorrow. I feel terribly sorry for missing the chance of so a happy get-together. I hope that all of you enjoying a good time. Is it possible for you and I to have a private meeting afterward? If so, please don't hesitate to tell me your preferable dates. I am eager for a pleasant chat about you.

    Please allow me say sorry again.

次生演替是指在原有植被虽已不存在，但原有土壤条件基本保留，甚至还保留了植物的____ 的地方发生演替，如火灾过后的草原、过量砍伐的森林、弃耕的农田上进行的演替．